Robert Dudley, 1st Earl of Leicester KG (24 June 1532 – 4 September 1588), was an English nobleman, a favourite and close friend of Elizabeth I of England from her first year on the throne until his death. For many years he was a suitor for the Queen's hand; she giving him reason to hope. He was widely believed to be her lover.

Dudley's youth was overshadowed by the downfall of his family in 1553 after his father, the Duke of Northumberland, had unsuccessfully tried to establish Lady Jane Grey on the English throne. Robert Dudley was condemned to death but was rehabilitated with the help of Philip II of Spain, then England's king consort. On Queen Elizabeth's accession in November 1558 Dudley was appointed Master of the Horse. In October 1562 he became a privy councillor and in 1587 was appointed Lord Steward of the Royal Household. In 1564 Dudley became Earl of Leicester and from 1563 one of the greatest landowners in North Wales and the English West Midlands by royal grants.

Robert Dudley, Earl of Leicester was one of Elizabeth's leading statesmen, involved in domestic as well as foreign politics alongside William Cecil and Francis Walsingham. Although he adamantly refused to be married to Mary, Queen of Scots, Dudley was for a long time relatively sympathetic to her. From the mid-1580s he strongly advocated her execution. As patron of the Puritan movement he supported non-conforming preachers, but tried to mediate between them and the bishops within the Church of England. A champion also of the international Protestant cause, he led the English campaign in support of the Dutch Revolt from 1585–1587. His acceptance of the post of Governor-General of the United Provinces infuriated Queen Elizabeth. The expedition was a military and political failure and ruined the Earl financially. Leicester was engaged in many large-scale business ventures and a main backer of Francis Drake and other explorers and privateers. During the Spanish Armada the Earl was in overall command of the English land forces. In this function he invited Queen Elizabeth to visit her troops at Tilbury. This was the last of many events he organized over the years, the most spectacular being the festival at his seat Kenilworth Castle in 1575 on occasion of a three-week visit by the Queen. Dudley was a principal patron of the arts, literature, and the Elizabethan theatre.

Robert Dudley's private life interfered with his court career and vice versa. When his first wife, Amy Robsart, fell down a flight of stairs and died in 1560 he was free to marry the Queen. However, the resulting scandal very much reduced his chances in this respect. Popular rumours that he had arranged for his wife's death continued throughout his life, despite the coroner's jury's verdict of accident. For eighteen years he did not remarry for Queen Elizabeth's sake and when he finally did, his new wife, Lettice Knollys, was permanently banished from court. This and the death of his only legitimate son and heir were heavy blows. Shortly after the child's death in 1584 a virulent libel known as Leycester's Commonwealth was best-selling in England. It laid the foundation of a literary and historiographical tradition that often depicted the Earl as the Machiavellian "master courtier" and as a deplorable figure around Elizabeth I. More recent research has led to a reassessment of his place in Elizabethan government and society.

Robert Dudley was the fifth son of John Dudley, Duke of Northumberland and his wife Jane, daughter of Sir Edward Guildford. The Dudleys were a large and happy family, with thirteen children born. These were educated in Renaissance Humanism, having such instructors as John Dee, Thomas Wilson, and Roger Ascham. Roger Ascham thought that his pupil Robert had an uncommon talent for languages and writing, "exceed[ing] almost all other by nature", and regretted that he had done himself harm by preferring "Euclid's pricks and lines" (mathematics). The craft of the courtier Robert learnt at the courts of Henry VIII and Edward VI. "My bringing-up has been too long about Princes to misuse anything towards them", he would summarize his lessons.

In 1549 Robert Dudley participated in crushing Ket's Rebellion and probably first met Amy Robsart, whom he was to wed on 4 June 1550 in the presence of the young King Edward. She was of the same age as the bridegroom and the daughter and heiress of Sir John Robsart, a gentleman-farmer of Norfolk. It was a love-match and the young couple depended heavily on both their fathers' gifts, especially Robert's. John Dudley, who since early 1550 effectively ruled England, was pleased to strengthen his influence in Norfolk by his son's marriage. Lord Robert, as he was styled as a duke's son, became an important local gentleman and a Member of Parliament. His court career went on in parallel.

On 6 July 1553 King Edward VI died and the Duke of Northumberland attempted to transfer the English Crown to Lady Jane Grey, his daughter-in-law, who was married to his youngest son, Guilford Dudley. Robert Dudley led a force of three hundred into Norfolk where Mary Tudor was assembling her followers. After some ten days in the county and securing several towns for Queen Jane, he took King's Lynn and proclaimed her on the market-place. The next day, 19 July, the reign of Queen Jane was over in London. Soon, the townsmen of King's Lynn seized Robert Dudley and the small rest of his troop and sent him to Framlingham Castle before Queen Mary. He was imprisoned in the Tower of London, attainted, and condemned to death, along with his father and four brothers. His father went to the scaffold. In the Tower, Dudley's stay coincided with the imprisonment of his childhood friend, Princess Elizabeth, who had been sent there on the orders of her half-sister, the Queen. It cannot be ruled out that they met in the Tower, even if not on the leads of the Bell Tower, as popular legend would have it. Yet, Robert Dudley and his brother Guilford were allowed to walk on "the leads in the Bell Tower". Guilford Dudley was executed in February 1554. The surviving brothers were released in the autumn; working their release, their mother (who died in January 1555) and their brother-in-law, Henry Sidney, had befriended the Spanish nobles around the new king consort, Prince Philip of Spain. Robert Dudley later frequently acknowledged that it was King Philip "to whom he owed his life".

The Dudley brothers were only welcome at court as long as King Philip was there, otherwise they were even suspected of associating with people who conspired against Mary's regime. In January 1557 Robert and Amy Dudley were allowed to repossess some of their former lands, but Dudley was already heaping up considerable debts. In March of the same year he was at Calais where he was chosen to deliver personally to Queen Mary the happy news of her husband's return to England. Ambrose, Robert, and Henry Dudley, now the youngest brother, fought for Philip II at the Battle of St. Quentinin August 1557. Henry Dudley was killed in the battle by a cannonball, according to Robert before his own eyes.

Robert Dudley was associated with Princess Elizabeth in 1557–1558, and he was counted among her special friends by Philip II's envoy to the English court a week before Queen Mary's death. He was quite possibly with Elizabeth when she first received news that she was Queen of England. She immediately made him Master of the Horse, an important court position entailing close attendance on the Queen. The post suited him, as he was a skilled horseman and showed great professional interest in royal transport and accommodation, horse breeding, and the supply of horses for all occasions. Dudley was also entrusted with organizing and overseeing a large part of the Queen's coronation festivities. In April 1559 Dudley was elected a Knight of the Garter in the good company of England's only duke and an earl, causing great wonder. The ambassador of the neutral Republic of Venice, by his office the most detached of the foreign envoys, soon wrote home: "My Lord Robert Dudley is ... very intimate with Her Majesty. On this subject I ought to report the opinion of many but I doubt whether my letters may not miscarry or be read, wherefore it is better to keep silence than to speak ill." Philip II had already been informed shortly before Dudley's decoration:

Lord Robert has come so much into favour that he does whatever he likes with affairs and it is even said that her majesty visits him in his chamber day and night. People talk of this so freely that they go so far as to say that his wife has a malady in one of her breasts^{[fn 1]} and the Queen is only waiting for her to die to marry Lord Robert ... Matters have reached such a pass ... that ... it would ... be well to approach Lord Robert on your Majesty's behalf ... Your Majesty would do well to attract and confirm him in his friendship.^[36]

Within a month, the Spanish ambassador, Count de Feria, counted Robert Dudley among those three persons who "rule everything". Visiting foreigners of princely rank were bidding for his goodwill. He acted as official host on state occasions and was himself a frequent guest at ambassadorial dinners. By the autumn of 1559 several foreign princes were vying for the Queen's hand; their envoys had the impression that Elizabeth and Dudley were only fooling them "until this wicked deed of killing his wife is consummated." "Lord Robert", the new Spanish ambassador, de Quadra, was convinced, was the man "in whom it is easy to recognize the king that is to be ... she will marry none but the favoured Robert." Many of the nobility would not brook Dudley's new prominence, as they could not "put up with his being King." Dudley's chief enemy at the time, the Duke of Norfolk, threatened that Dudley "would not die in his bed", and the Imperial envoy marvelled that he had "not been slain long ere this." Plans to kill the favourite abounded; one plot that remained a secret at the time was hatched by the Swedish ambassador. Dudley took to wearing a light coat of mail under his clothes. Among all classes, in England and abroad, gossip got under way that the Queen had children by Dudley; the rumours never quite ended for the rest of her life.

Already in April 1559 court observers noted that Elizabeth never let Dudley from her side. Lady Amy Dudley lived in different parts of the country since her ancestral manor house was uninhabitable. Her husband visited her for four days at Easter 1559 and she spent a month around London some weeks later; it is unknown whether they saw each other ever again. Dudley had apparently been planning a visit to her for months, postponing it for court duties, when she was found dead at her residence Cumnor Place near Oxford on 8 September 1560. Dudley was with the Queen at Windsor Castle. Staying near London, away from the putative crime scene, he pressed for an impartial inquiry which had already begun in the form of an inquest. The jury found that it was an accident: Lady Dudley, staying alone "in a certain chamber", had fallen down the adjoining stairs, sustaining two head injuries and breaking her neck. It was widely believed that Dudley had arranged his wife's death to be able to marry the Queen. The scandal played into the hands of nobles and politicians who desperately tried to prevent Elizabeth from marrying him. Some of these, like William Cecil and Nicholas Throckmorton, made use of it, but did not themselves believe Dudley to be guilty of murdering his wife. Elizabeth remained close with Dudley and he pursued his suit for the Queen's hand in an atmosphere of political intrigue. His wife's and his father's shadows haunted his prospects. Pope Pius IV explained to one of his cardinals:

the greater part of the nobility of that island take ill the marriage which the said queen designs to enter with the Lord Robert Dudley ... they fear that if he becomes king, he will want to avenge the death of his father, and extirpate the nobility of that kingdom.

Elizabeth countered such notions, saying that Lord Robert "was of a very good disposition and nature, not given by any means to seek revenge of former matters past".

In October 1562 the Queen fell ill with smallpox and, believing her life to be in danger, she asked the Privy Council to make Robert Dudley Protector of the Realm and to give him a suitable title together with twenty thousand pounds a year. There was universal relief when she recovered her health; Dudley was made a privy councillor. He was already deeply involved in foreign politics, including Scotland. In 1563 Elizabeth suggested Dudley as a consort to the widowed Mary, Queen of Scots; this would be ideal to achieve firm amity between England and Scotland, diminishing the influence of foreign powers. Her proposal was also to be a compensation for not marrying Dudley herself, "whom, if it might lie in our power, we would make owner or heir of our own kingdom." Mary of Scotland at first inquired if Elizabeth was serious, wanting above all to know her chances of inheriting the English crown. Elizabeth let it be known, repeatedly, that she was only prepared to declare Mary her acknowledged heir on condition that she marry Dudley, "and ... none else". Mary's advisors warmed much to the prospect of having Dudley as their prince. In September 1564 Elizabeth bestowed on him the earldom of Leicester, a move, in planning for years, which made him more acceptable to Mary. Cecil hinted to the Scots that more was to follow. In early 1565 Thomas Randolph, the English ambassador to Scotland, was told by the Scottish queen that she would accept the proposal. To his amazement, Dudley was not to be moved to comply. Dudley indeed had made it clear to the Scots at the beginning that he was not a candidate for Mary's hand and forthwith had behaved with passive resistance. He also worked in the interest of Henry Stuart, Lord Darnley, Mary's eventual choice of husband. Elizabeth herself had wavered as to declaring Mary her heir; still, she finally told the Spanish ambassador that the proposal fell through because the Earl of Leicester refused to cooperate.

By 1564 Dudley had realised that his chances of becoming Elizabeth's consort were small. At the same time he could not "consider ... without great repugnance", as he said, that she chose another husband. Confronted with other marriage projects, Elizabeth continued to say that she still would very much like to marry him. Dudley was seen as a serious candidate until the mid-1560s and later. To remove this threat to Habsburg and Valois suitors, between 1565 and 1578, four German and French princesses were mooted as brides for Leicester, as a consolation for giving up Elizabeth and his resistance to her foreign marriage projects. These he had and would continue to sabotage. In 1566 Dudley formed the opinion that Elizabeth would never marry, recalling that she had always said so since she was eight years old; but he still was hopeful — she had also assured him he would be her choice in case she changed her mind (and married an Englishman). He was not alone in this assessment; the previous year, Philip II had written: "and after all, she will either not marry or else marry Robert, to whom she has always been so much attached ... the Queen is in love with Robert". Even as she did not marry him, Dudley's intimacy with the Queen gave him a type of influence that other councillors hardly had. His apartments at court adjoined the Queen's, in every residence. Another side of such privileges was Elizabeth's possessiveness and jealousy of his person and company. For more than two decades he would not be allowed to go abroad and even short absences from court were taken offence with. Dudley's presence was crucial to the smooth functioning of the court and Elizabeth's well-being. When the Earl was absent for a few weeks in 1578, Sir Christopher Hatton reported a growing emergency: "This court wanteth your presence. Her majesty is unaccompanied and, I assure you, the chambers are almost empty."

Personally, Elizabeth's "surrogate husband", Dudley was an unofficial consort on many ceremonial occasions, sometimes acting in the Queen's stead. In a personal letter to the Earl of Shrewsbury, an old friend of Leicester's, Elizabeth said she considered Leicester as "another ourself". Dudley largely assumed charge of court ceremonial and organized hundreds of small and large festivities, being responsible for entertaining Elizabeth's guests. Though he did not "delight in banquets", he had a peculiar taste for exotic fruits and salads — and French cooks. From 1587 he was Lord Steward, being responsible for the royal household's supply with food and other commodities. He displayed a strong sense for economizing and reform in this function, which he had de facto occupied long before his official appointment. The sanitary situation in the palaces was a perennial problem and a talk with Leicester about these issues inspired John Harington to construct a water closet. Leicester was a lifelong sportsman, hunting and and jousting in the tiltyard. As the Queen's dancing partner his "high magnificence ... astonished beholders". He was also an indefatigable tennis-player; sometimes Elizabeth watched: One morning in 1565 Dudley "took the Queen's napkin out of her hand and wiped his face". His tennis-partner, the Duke of Norfolk, was outraged, swearing Leicester "was too saucy, and ... that he would lay his racket upon his face"; Elizabeth was angry with the Duke and armed followers of Norfolk and Leicester, wearing their respective colours, soon patrolled the court.

After the Duke of Northumberland's attainder the entire Dudley inheritance had disappeared. His sons had to start from scratch in rebuilding the family fortunes, as they had renounced any rights to their father's former possessions or titles when their own attainder had been lifted in 1558. In the first years of the new reign Dudley's financial situation was very precarious and he could only finance the lifestyle expected of a royal favourite by large loans from City of London merchants. With time Elizabeth's material generosity towards Dudley proved singular, his most important sources of income deriving from monopolies and export licences. In 1563, in anticipation of his peerage, the Queen granted Dudley Kenilworth Manor, Castle, and Park, a large Warwickshire possession of the Crown, together with the lordships of Denbigh and Chirk in North Wales. Other grants were to follow. All in all, Leicester and his elder brother, Ambrose, Earl of Warwick, presided over the greatest aristocratic interest in the West Midlands and North Wales.

At the time Robert Dudley entered his new Welsh possessions there had existed a tenurial chaos for more than half a century. Some leading local families benefitted from this to the detriment of the Crown's revenue. To remedy this situation, Dudley effected compositions with the tenants. In exchange for newly agreed rents all tenants that had so far only been copyholders were raised to the status of freeholders at one stroke. Additionally, all tenants' rights of common were secured as were the boundaries of the commons, striking a balance between property rights and protection against enclosure. The increase in revenue Leicester achieved for himself was much lower than traditionally thought. Simon Adams, who has researched Dudley's Welsh connections in depth, concludes: "the tenurial reformation he undertook in the lordships of Denbigh and Chirk reveals an administrative ability that has often been overlooked. This was an ambitious resolution of a long-standing problem ... without parallel in Elizabeth's reign." Within Denbighshire Leicester challenged and checked the complete domination of the county by the Salusbury family, a situation which pleased other families. Dudley set about developing the town of Denbigh with large building projects; the church he planned, though, was never finished, being too ambitious. It would not only have been the largest, but also the first post-Reformation church in England and Wales built according to a plan where the preacher was to take the centre instead of the altar, thus stressing the importance of preaching in the Protestant Church. In vain Leicester tried to have the nearby episcopal see of St. Asaph transferred to Denbigh. He also encouraged and supported the translation of the Bible and the Common Prayer Book into Welsh.

Ambrose and Robert Dudley were very close, in matters of business and personally. Through their paternal grandmother, they descended from the Hundred Years War heroes, John Talbot, 1st Earl of Shrewsbury, and Richard Beauchamp, Earl of Warwick. Robert Dudley was especially fascinated by the Beauchamp descent and, with his brother, adopted the ancient heraldic device of the earls of Warwick, the bear and ragged staff. Due to such genealogical aspects the West Midlands held a special significance for him. He went to great lengths and spent absurd sums to acquire specific lands in his attempt to rebuild and perpetuate the House of Dudley. The town of Warwick felt this during a magnificent visit by the Earl in 1571, for a celebration of the feast of the order of Saint Michael. With the latter Dudley had been invested by the French king in 1566. "Aparelled all in white ... the proportions and lineaments of his body" made such an impression that he was accounted "the goodliest [best looking] male personage in England" by the onlookers. By these festivities Leicester celebrated himself as the heir of the Beauchamps. Lord Leycester's Hospital, a charity for aged and injured soldiers still functioning today, he founded shortly afterwards in the same spirit.

Kenilworth Castle was the centre of Leicester's ambitions to "plant" himself in the region. He holidayed at the castle almost every year from 1570. In July 1575 he staged a final allegorical bid for the Queen's hand in the form of a nineteen-day-festival. There were a Lady of the Lake, a swimming papier-mâché dolphin with a little orchestra in its belly, fireworks, masques, hunts, and popular entertainments like bear baiting. The whole scenery of landscape, artificial lake, castle, and renaissance garden was ingeniously used for the entertainment. When Elizabeth arrived, time stood literally still, as the great tower clock of the castle was stopped for the time of her visit. Confronted by a Puritan friend with rumours about his "ungodly life", Dudley defended himself in 1576:

I stand on the top of the hill, where ... the smallest slip seemeth a fall ... I may fall many ways and have more witnesses thereof than many others who perhaps be no saints neither ... for my faults ... they lie before Him who I have no doubt but will cancel them as I have been and shall be most heartily sorry for them.

With Lady Douglas Sheffield, a young widow of the Howard family, he had a serious relationship from the late 1560s. He explained to her that he could not marry, not even in order to beget a Dudley heir, without his "utter overthrow":

You must think it is some marvellous cause ... that forceth me thus to be cause almost of the ruin of mine own house ... my brother you see long married and not like to have children, it resteth so now in myself; and yet such occasions is there ... as if I should marry I am sure never to have [the Queen's] favour".

Although in this letter Leicester said he still loved her as he did at the beginning, he offered her his help to find another husband for reasons of respectability if she so wished. The affair continued and in 1574 Lady Douglas gave birth to a son, also called Robert Dudley.

Lettice Knollys was the wife of Walter Devereux, 1st Earl of Essex and first cousin once removed of Queen Elizabeth on her mother's side. Leicester had flirted with her in the summer of 1565, causing a prolonged outbreak of jealousy in the Queen. When Lord Essex went to Ireland in 1573, they probably became lovers. This caused much talk and "great enmity between the Earl of Leicester and the Earl of Essex" when the latter came home in December 1575. Leicester was in support of sending Essex back to Ireland, where he died soon of dysentery. Rumours of poison, administered by the Earl of Leicester's means, were soon abroad. An official investigation conducted by Henry Sidney, Lord Deputy of Ireland and Leicester's brother-in-law, did not find any indications of foul play but "a disease appropriate to this country ... whereof ... died many". The rumours continued. The prospect of marriage to the Countess of Essex on the horizon, Leicester wished to end his relationship with Lady Douglas Sheffield. She accepted his offer to provide for her only after a stormy meeting in the gardens of Greenwich, and refused to surrender custody of their son. Later young Robert was in his father's custody, however he came there. Leicester was very fond of him and gave him an excellent education; he often made a trip to visit him, and bequeathed to him the bulk of his estate after Ambrose Dudley's death. Douglas Sheffield remarried in 1579. In 1603, Elizabeth I having died, the younger Robert Dudley tried unsuccessfully to prove that his parents had married thirty years earlier in a secret ceremony. In that case he would have been able to claim the earldoms of Leicester and Warwick. His mother supported him, but maintained that she had been strongly against raising the issue. Leicester himself had throughout considered the boy as illegitimate.

On 21 September 1578 Leicester secretly married Lady Essex at his country house at Wanstead, with only a handful of relatives and friends present. He did not dare to tell the Queen of his marriage; nine months later Leicester's enemies at court acquainted her with the situation, causing a furious outburst. She already had been aware of his marriage plans a year earlier, though. Leicester's hope of an heir was fulfilled in 1581 when another Robert Dudley, styled Lord Denbigh, was born. The child died aged three in 1584, leaving behind disconsolate parents. Leicester found comfort in God since, as he wrote, "princes ... seldom do pity according to the rules of charity." The Earl turned out to be a devoted husband: In 1583 the French ambassador, Michel de Castelnau, wrote of "the Earl of Leicester and his lady to whom he is much attached", and "who has much influence over him". To all his four stepchildren Leicester was a concerned parent. In every respect he worked for the advancement of Robert Devereux, 2nd Earl of Essex, whom he regarded as his political heir.

The marriage of her favourite hurt the Queen deeply. She never accepted it, humiliating Leicester in public: "my open and great disgraces delivered from her Majesty's mouth". Then again, she would be as fond of him as ever. In 1583 she informed ambassadors that Lettice Dudley was "a she-wolf" and her husband a "traitor" and "a cuckold". Lady Leicester's social life was much curtailed. Even her movements could pose a political problem, as Francis Walsingham explained: "I see not her Majesty disposed to use the services of my Lord of Leicester. There is great offence taken at the conveying down of his lady." The Earl stood by his wife, asking his colleagues to intercede for her; there was no hope: "She [the Queen] doth take every occasion by my marriage to withdraw any good from me", Leicester wrote still after seven years of marriage.

As a privy councillor Robert Dudley was one of the most frequently attending and heavily involved in day-to-day business. In 1578 the Spanish ambassador Bernardino de Mendoza described Elizabeth's government: "although there are seventeen councillors ... the bulk of the business really depends upon the Queen, Leicester, Walsingham and Cecil". The last three have been called "the triumvirate" by Alan Haynes; while, for the first thirty years of the reign, Simon Adams sees William Cecil and Robert Dudley as "the most important councillors", working intimately with the Queen.

In 1560 the diplomat Nicholas Throckmorton advocated vehemently against Dudley marrying the Queen, but Dudley won him over in 1562. Throckmorton henceforth became his political advisor and intimate. After Throckmorton's death in 1571 there quickly evolved a political alliance between the Earl of Leicester and Sir Francis Walsingham, soon to be Secretary of State. Together they worked for a militant Protestant foreign policy. There also existed a family relationship between them after Walsingham's daughter had married Philip Sidney, Leicester's favourite nephew. Leicester, after some initial jealousy on his part, also became a good friend of Sir Christopher Hatton, himself one of Elizabeth's favourites. Robert Dudley's relationship with William Cecil, Lord Burghley was complicated. Traditionally they are seen as enemies, and Cecil behind the scenes sabotaged Dudley's endeavours to obtain the Queen's hand. On the other hand they were on friendly terms and had an efficient working relationship which never broke down. On the whole, Cecil and Dudley were in concord about policies while disagreeing fundamentally about some issues, such as the Queen's marriage and some areas of foreign policy. Cecil favoured the suit of Francois, Duke of Anjou in 1578–1581 for Elizabeth's hand, while Leicester was among its strongest opponents, even contemplating exile in a letter to Burghley. The Anjou courtship, at the end of which Leicester and several dozen noblemen and gentlemen escorted the French prince in triumph to Antwerp, also touched the question of English intervention in the Netherlands to help the rebellious provinces. This debate stretched over a decade until 1585, with the Earl of Leicester as the foremost interventionist. Burghley was more cautious of military engagement while in a dilemma over his Protestant predilections. In 1572 the vacant post of Lord High Treasurer was offered to Leicester; he declined and proposed Burghley, stating that the latter was the much more suitable candidate. In later years, being at odds, Dudley felt like reminding Cecil of their "thirty years friendship".

Until about 1571/1572 Dudley supported Mary Stuart's succession rights to the English throne. He was also, from the early 1560s, on the best terms with the Protestant lords in Scotland thereby supporting the English or, as he saw it, the Protestant interest. After Mary Stuart's flight into England (1568) Leicester was, unlike Cecil, in favour of restoring her as Scottish queen under English control, preferably with a Protestant English husband — as long as he himself would not be the intended bridegroom (which had been suggested). "For there is danger from delivering of her to her Government, so is there danger in retaining her in prison", he wrote in 1571. Shortly after the St. Bartholomew's Day Massacre in 1572 Cecil, Leicester, and Elizabeth engaged in a top-secret plan to extradite Mary to the Scottish regency government, who would then immediately execute her. The scheme failed due to the unexpected death of the Scottish regent. In 1577 Leicester had a courteous meeting with Mary, lending a sympathetic ear to her complaints of captivity. As Mary might be their future sovereign, Elizabeth's ministers had cause to show their goodwill towards the captive Queen now and then; Leicester's was at an end in 1584. He was stung by the publication of the Catholic anti-Leicester libel, Leicester's Commonwealth, thinking that Mary was involved in its conception. "Leicester has lately told a friend that he will persecute you to the uttermost", she was informed.

Dudley was probably behind the Bond of Association, which the Privy Council gave out in October 1584. Being circulated in the country, the subscribers swore that, should Elizabeth be assassinated (as William the Silent had been a few months earlier), not only the killer but also the royal person who would benefit from this should be executed. In 1586 Walsingham uncovered the Babington Plot; after the Ridolfi Plot (1571), and the Throckmorton Plot (1583), this was a further scheme to assassinate Elizabeth in which Mary was involved. Following her conviction, Leicester, then in the Netherlands, vehemently urged her execution in his letters; he despaired of Elizabeth's security after so many plots. Back in England, he met James VI's delegate in his coach. The Scot had been sent to demand that Mary's life be spared. After having bluntly emphasized how desireable Mary's death would be to James, Leicester was left with the impression that the King would not try to avenge his mother's execution, his succession to the English Crown provided. King James' own tacit, but important, approval followed between the lines in a sophisticated letter to the Earl. In February 1587 Elizabeth signed Mary's death warrant with the proviso that it be not carried out until she gave green light. As there was no sign of her doing so, some members of the Privy Council decided to proceed with Mary's execution in the interest of the state, against Elizabeth's wishes. They were, among others, Burghley and Leicester, but not Walsingham who was ill. The Queen's anger at the news of Mary's death was terrifying. Despite all pleadings Burghley was not allowed into the royal presence for several months. Leicester went to Bath and Bristol for his health; yet, unlike the other culprits and to Burghley's dismay, he escaped Elizabeth's personal wrath entirely.

Robert Dudley was a pioneer of new industries; interested in many things from tapestries to mining, he was engaged in the first joint stock companies in English history. The Earl also concerned himself with relieving unemployment among the poor. On a personal level, he gave to poor people, petitioners, and prisons on a daily basis. Due to his interests in trade and exploration, as well as his debts, his contacts with the London city fathers were intense. He was an enthusiastic investor in the Muscovy Company and the Merchant Adventurers. English relations with Morocco were also handled by Leicester. This he did in the manner of his private business affairs, underpinned by a patriotic and missionary zeal (commercially, these relations were a losing business). Much interest he took in the careers of John Hawkins and Francis Drake, from early on, and he was a principal backer of Drake's circumnavigation of the world. Robert and Ambrose Dudley were also principal patrons of Martin Frobisher's 1576 search for the Northwest Passage. Later Leicester acquired his own ship, the Galleon Leicester, which he employed in a luckless expedition under Edward Fenton, but also under Drake. As much as profit, English seapower was on his mind and accordingly, Leicester became a friend and leading supporter of Dom António, the exiled claimant to the Portuguese throne after 1580.

Apart from their legal function the Inns of Court were the Tudor equivalents of gentlemen's clubs. In 1561, grateful for favours he had done them, the Inner Temple admitted Dudley as their most privileged member, their "Lord and Governor". He was allowed to build his own apartments on the premises and organized grand festivities and performances in the Temple. As Chancellor of Oxford University Dudley was highly committed, if somewhat authoritarian. He frowned upon the dangerous play of football and the extravagant clothing of students. Leicester enforced the Thirty-nine Articles and the oath of royal supremacy at Oxford, and obtained from the Queen an incorporation by Act of Parliament for the university. He was also instrumental in refounding Oxford University Press. He installed the pioneer of international law, Alberico Gentili, and the exotic theologian, Antonio del Corro, at Oxford; over del Corro's controversial case, Leicester even sacked the university's Vice-Chancellor.

From at least 1559 Dudley had his own company of players, and in 1574 obtained for them the first royal patent that was ever issued to actors so that they could tour the country unmolested by the authorities. In 1577 he helped James Burbage, the former joiner and now head of Leicester's Men, to erect the first permanent English theatre building, called:The Theatre. Again in 1559, Robert Dudley suggested to the tailor John Stow to become a chronicler, according to Stow's own words in 1604.

Leicester possessed one of the largest and finest collections of paintings in Elizabethan England, being the first great private collector. He was a principal patron of Nicholas Hilliard, a garden design enthusiast, and interested in all aspects of Italian culture. The Earl's circle of scholars and literary men included, among others, his nephew Philip Sidney, the astrologer and Hermeticist John Dee (his former tutor), his secretaries Edward Dyer and Jean Hotman, as well as John Florio and Gabriel Harvey. Through Harvey, Edmund Spenser found employment at Leicester House on the Strand, the Earl's palatial town house; there he wrote his first works of poetry. Many years after Leicester's death Spenser wistfully recalled this time in his Prothalamion, and in 1591 remembered the late Earl with his poem The Ruins of Time.

Robert Dudley's religion, which had always been Protestant, showed some inconsistencies during the early years of Elizabeth's reign. He was the most significant patron to returning Puritan exiles and protected radical Protestants as well as Catholics from the church authorities. Dudley supported the French Huguenots but also had excellent contacts with the papacy. By the later 1560s he was fully identified with advanced Protestantism; in 1568 the French ambassador described him as "totally of the Calvinist religion". After the St. Bartholomew's Day Massacre in 1572, this trait in him became the more pronounced, and he continued as the chief patron of English Puritans and a champion of international Calvinism. Dudley went to great lengths to support non-conforming preachers, while warning them against too radical positions which, he argued, would only endanger what reforms had been hitherto achieved. He would not condone the overthrow of the existing church model because of "trifles", he said: "I am not, I thank God, fantastically persuaded in religion but ... do find it soundly and godly set forth in this universal Church of England." Accordingly, he tried to smooth things out and, among other moves, initiated several disputations between the more radical elements of the church and the episcopal side so that they "might make reconcilement". His influence in ecclesiastical matters was considerable until it declined in the 1580s under Archbishop John Whitgift. Dudley was instrumental in preferring at least six of the earliest Elizabethan bishops, all exiles, to their sees; among them Edmund Grindal, Edwin Sandys and Thomas Young. All these bishops felt themselves obliged to him. Many of the highest clergy had been and considered themselves as his servants. The Earl expected them to follow his orders and, in 1578, he scolded Bishop Edmund Scambler and his colleagues for forgetting formerly held ideals: "The care of this world truly hath choked you all, yea almost all". Leicester was especially interested in the furtherance of preaching, which was the main concern of moderate Puritanism. He backed this brand of Puritanism in counties where he had influence and habitually appeared at public preaching exercises when travelling in the country. On the other hand, in his household, Leicester employed Catholics like Sir Christopher Blount, who held a position of trust and of whom he was personally fond. The Earl's patronage of and reliance on individuals was as much a matter of old family loyalties or personal relationships as of religious allegiances. Such ties explain Leicester's concern for Edmund Campion, who had been the Earl's protégé at Oxford University and in his service for a time, before he went abroad to become a Jesuit. After his arrest in 1581 he was imprisoned in the Tower of London in a tiny cell where he could neither stand nor lie down. Leicester and the Earl of Bedford examined him in Leicester House, offering him his life and liberty if he returned to the Protestant faith. Campion would not do that. A contemporary Italian account reports: "The Earls greatly admired his virtue and learning ... and said it was a pity he was a papist ... They ordered his heavy irons to be removed and that [he be given] a bed and other necessaries".

During the 1570s Leicester built a special relationship with Prince William of Orange, who held him in high esteem. The Earl became generally popular in the Netherlands. Since 1577 he pressed for an English military expedition, led by himself (as the Dutch strongly wished) to succour the rebels. In 1584 the Prince of Orange was murdered, political chaos ensued, and in July 1585 Antwerp fell to the Duke of Parma. An English intervention was inevitable. It was decided that Leicester would go to the Netherlands and "be their chief as heretofore was treated of", as he phrased it in August 1585. He was alluding to the recently signed Treaty of Nonsuch in which his position and authority as "governor-general" of the Netherlands had only been vaguely defined. At the end of December 1585 Leicester was received in the Netherlands, according to one correspondent, in the manner of a second Charles V; a Dutch town official already noted in his minute-book that the Earl was going to have "absolute power and authority". After a progress through several cities and so many festivals he arrived in The Hague, where on 1 January 1586 he was urged to accept the title governor-general by the States General of the United Provinces. Leicester wrote to Burghley and Walsingham, explaining why he believed the Dutch importunities should be answered favourably. He accepted his elevation on 25 January, having not yet received any communications from England due to constant adverse winds. The Earl had now "the rule and government general" with a Council of State to support him (the members of which he nominated himself). He remained a subject of Elizabeth, making it possible to contend that she was now sovereign over the Netherlands. According to Leicester, this was what the Dutch desired. From the start such a position for him had been implied in the Dutch propositions to the English, and in their instructions to Leicester; and it was consistent with the Dutch understanding of the Treaty of Nonsuch. The English queen, however, in her instructions to Leicester, had expressly declined to accept offers of sovereignty from the United Provinces while still demanding of the States to follow the "advice" of her lieutenant-general in matters of government. Her ministers on both sides of the Channel hoped she would accept the situation as a fait accompli and could even be persuaded to add the rebellious provinces to her possessions. Instead her fury knew no bounds and Elizabeth sent Sir Thomas Heneage to read out her letters of disapproval before the States General, Leicester having to stand nearby. Elizabeth's "commandment" was that the Governor-General immediately resign his post in a formal ceremony in the same place where he had taken it. After much pleading with her and protestations by the Dutch, it was postulated that the governor-generalship had been bestowed not by any sovereign, but by the States General and thereby by the people. The damage was done, however: "My credit hath been cracked ever since her Majesty sent Sir Thomas Heneage hither", Leicester recapitulated in October 1586. Elizabeth demanded of her Lieutenant-General to refrain at all cost from any decisive action with Parma, which was the opposite of what Leicester wished and what the Dutch expected of him. After some initial successes, the unexpected surrender of the strategically important town of Grave was a serious blow to English morale. Leicester's fury turned on the town's governor, Baron Hemart, whom he had executed despite all pleadings. The Dutch nobility were astonished: even the Prince of Orange would not have dared such an outrage, Leicester was warned; but, he wrote, he would not be intimidated by the fact that Hemart "was of a good house". Leicester's forces, heavily underfinanced and small, faced the most formidable army in Europe. Elizabeth for many months delayed sending promised funds and troops, much aggravating the soldiers' lot. "They cannot get a penny; their credit is spent; they perish for want of victuals and clothing in great numbers ... I assure you it will fret me to death ere long to see my soldiers in this case and cannot help them.", Leicester wrote home. Four months later, mass desertions occurring, he commented: "I do but wonder to see they do not rather kill us all than run away, God help us!"

Many Dutch statesmen were essentially politiques; they soon became disenchanted with the Earl's enthusiastic fostering of what he called "the religion". His most loyal friends were the Calvinists at Utrecht and Friesland, provinces in constant opposition to Holland and Zeeland. Those rich provinces engaged in a lucrative trade with Spain which was very helpful to either side's war effort. Encouraged by the poorer sections of Dutch society, Leicester enforced a ban on this trade with the enemy, thus alienating the wealthy Dutch merchants. He also effected a fiscal reform. In order to centralize finances and to replace the highly corrupt tax farming with direct taxation, a new Council of Finances was established which was not under supervision of the Council of State. The Dutch members of the Council of State were outraged at these bold steps. English peace talks with Spain behind Leicester's back, which had started within days after he had left England, undermined his position further. In September 1586 there was a skirmish at Zutphen, in which Philip Sidney was wounded. He died a few weeks later. His uncle's grief was great. In December Leicester returned to England. In his absence, William Stanley and Rowland York, two Catholic officers whom Leicester had placed in command of Deventer and the fort of Zutphen, respectively, went over to Parma, along with their key fortresses — a disaster for the Anglo-Dutch coalition in every respect. His Dutch friends, as his English critics, pressed for Leicester's return to the Netherlands. Shortly after his arrival in June 1587 the English-held port of Sluis was lost to Parma, Leicester being unable to assert his authority over the Dutch allies, who refused to cooperate in relieving the town. After this blow Elizabeth, who ascribed it to "the malice or other foul error of the States", was happy to enter into peace negotiations with the Duke of Parma. By December 1587 the differences between Elizabeth and the Dutch politicians, with Leicester in between, had become insurmountable; he asked to be recalled by the Queen and gave up his post. He was irredeemably in debt because of his personal financing of the war.

In July 1588, as the Spanish Armada came nearer, the Earl of Leicester was appointed "Lieutenant and Captain-General of the Queen's Armies and Companies". At Tilbury on the Thames he erected a camp for the defence of London, should the Spaniards indeed land. Leicester vigorously counteracted the disorganization he found everywhere, having few illusions about "all sudden hurley-burleys", as he wrote to Walsingham. When the Privy Council was already considering to disband the camp to save money, Leicester held against it, setting about to plan with the Queen a visit to her troops. On the day she gave her famous speech he walked beside her horse bare-headed. After the Armada the Earl was seen riding in splendour through London "as if he were a king". For the past weeks he had usually dined with the Queen, a unique favour. On his way to Buxton in Derbyshire to take the baths, he died at Cornbury Park near Oxford on 4 September 1588. A man named Smith claimed to have bewitched the Earl into eternity; the Privy Council decided on malaria and let Smith go free. The Earl's health had not been good for some time, and as causes of death historians have considered malaria, but also stomach cancer or a heart condition. Only a week earlier Leicester had said farewell to his Queen. Elizabeth was deeply affected and locked herself in her apartment for a few days until Lord Burghley had the door broken. Her nickname for Dudley was "Eyes", which was symbolized by the sign of ôô in their letters to each other. Elizabeth kept the letter he had sent her six days before his death in her bedside treasure box, endorsing it with "his last letter" on the outside. It was still there when she died fifteen years later.

Leicester was buried, as he had requested, in the Beauchamp Chapel in Collegiate Church of St Mary, Warwick — in the same chapel as Richard Beauchamp, his ancestor, and the "noble Impe", his little son. Countess Lettice was also buried there when she died in 1634, alongside the "best and dearest of husbands", as the epitaph, which she commissioned, says.