Suleiman I, His Imperial Majesty Grand Sultan, Commander of the Faithful and Successor of the Prophet of the Lord of the Universe (Ottoman Turkish: سليمان Süleymān, Modern Turkish: Süleyman; 6 November 1494  – 5/6/7 September 1566) was the tenth and longest-reigning Sultan of the Ottoman Empire, from 1520 to his death in 1566. He is known in the West as Suleiman the Magnificent and in the East, as the Lawmaker (in Turkish Kanuni; Arabic: القانونى‎, al‐Qānūnī), for his complete reconstruction of the Ottoman legal system. Suleiman became a prominent monarch of 16th century Europe, presiding over the apex of the Ottoman Empire's military, political and economic power. Suleiman personally led Ottoman armies to conquer the Christian strongholds of Belgrade, Rhodes, and most of Hungary before his conquests were checked at the Siege of Vienna in 1529. He annexed most of the Middle East in his conflict with the Persians and large swathes of North Africa as far west as Algeria. Under his rule, the Ottoman fleet dominated the seas from the Mediterranean to the Red Sea and the Persian Gulf.

At the helm of an expanding empire, Suleiman personally instituted legislative changes relating to society, education, taxation, and criminal law. His canonical law (or the Kanuns) fixed the form of the empire for centuries after his death. Not only was Suleiman a distinguished poet and goldsmith in his own right; he also became a great patron of culture, overseeing the golden age of the Ottoman Empire's artistic, literary and architectural development. He spoke four languages: Persian, Arabic, Serbian and Chagatay (a Turkic language related to Uighur and Uzbek). In a break with Ottoman tradition, Suleiman married a harem girl, Roxelana, who became Hürrem Sultan; her intrigues as queen in the court and power over the Sultan made her quite renowned. Their son, Selim II, succeeded Suleiman following his death in 1566 after 46 years of rule.

Suleiman was born in Trabzon along the coast of the Black Sea, probably on 6 November 1494. His mother was Valide Sultan Aishe Hafsa Sultan or Hafsa Hatun Sultan, who died in 1534. At the age of seven, he was sent to study science, history, literature, theology, and military tactics in the schools of the Topkapı Palace in Constantinople. As a young man, he befriended Ibrahim, a slave who later became one of his most trusted advisers. From the age of seventeen, young Suleiman was appointed as the governor of first Kaffa (Theodosia), then Sarukhan (Manisa) with a brief tenure at Edirne. Upon the death of his father, Selim I (1465 – 1520), Suleiman entered Istanbul and acceded to the throne as the tenth Ottoman Sultan. An early description of Suleiman, a few weeks following his accession, was provided by the Venetian envoy Bartolomeo Contarini: "He is twenty-five years of age, tall, but wiry, and of a delicate complexion. His neck is a little too long, his face thin, and his nose aquiline. He has a shade of a moustache and a small beard; nevertheless he has a pleasant mien, though his skin tends to pallor. He is said to be a wise Lord, fond of study, and all men hope for good from his rule. His turban is also excessively large." Some historians claim that in his youth Suleiman had an admiration for Alexander the Great. He was influenced by Alexander's vision of building a world empire that would encompass the east and the west, and this created a drive for his subsequent military campaigns in Asia and in Africa, as well as in Europe.

Upon succeeding his father, Suleiman began a series of military conquests, eventually suppressing a revolt led by the Ottoman-appointed governor of Damascus in 1521. Suleiman soon made preparations for the conquest of Belgrade from the Kingdom of Hungary — something his great-grandfather Mehmed II had failed to achieve. Its capture was vital in eliminating the Hungarians who, following the defeats of the Serbs, Bulgarians and Byzantines, remained the only formidable force who could block further Ottoman gains in Europe. Suleiman encircled Belgrade and began a series of heavy bombardments from an island in the Danube. With a garrison of only 700 men, and receiving no aid from Hungary, Belgrade fell in August 1521. News of the conquest of one of Christendom's major strongholds spread fear across Europe. As the ambassador of the Holy Roman Empire to Istanbul was to note, "The capture of Belgrade was at the origin of the dramatic events which engulfed Hungary. It led to the death of King Louis, the capture of Buda, the occupation of Transylvania, the ruin of a flourishing kingdom and the fear of neighbouring nations that they would suffer the same fate…"

The road to Hungary and Austria lay open, but Suleiman diverted his attention to the Eastern Mediterranean island of Rhodes, the home base of the Knights Hospitaller, whose activities as pirates near Asia Minor and the Levant had posed a perennial problem to Ottoman interests. In the summer of 1522, taking advantage of the navy he inherited from his father, Suleiman dispatched an armada of some 400 ships whilst personally leading an army of 100,000 across Asia Minor to a point opposite the island. Following a siege of five months with brutal encounters, Rhodes capitulated and Suleiman allowed the Knights of Rhodes to depart. They eventually formed their new base in Malta.

As relations between Hungary and the Ottoman Empire deteriorated, Suleiman resumed his campaign in Eastern Europe and on 29 August 1526, he defeated Louis II of Hungary (1506–26) at the Battle of Mohács. In its wake, Hungarian resistance collapsed and the Ottoman Empire became the pre-eminent power in Eastern Europe. Upon encountering the lifeless body of King Louis, Suleiman is said to have lamented: "I came indeed in arms against him; but it was not my wish that he should be thus cut off while he scarcely tasted the sweets of life and royalty."

Under Charles V and his brother Ferdinand, Archduke of Austria, the Habsburgs reoccupied Buda and took Hungary. As a result, in 1529, Suleiman once again marched through the valley of the Danube and regained control of Buda and in the following autumn laid siege to Vienna. It was to be the Ottoman Empire's most ambitious expedition and the apogee of its drive towards the West. With a reinforced garrison of 16,000 men, the Austrians inflicted upon Suleiman his first defeat, sowing the seeds of a bitter Ottoman-Habsburg rivalry which lasted until the 20th century. A second attempt to conquer Vienna failed in 1532, with Suleiman retreating before reaching the city. In both cases, the Ottoman army was plagued by bad weather (forcing them to leave behind essential siege equipment) and was hobbled by overstretched supply lines.

By the 1540s a renewal of the conflict in Hungary presented Suleiman with the opportunity to avenge the defeat suffered at Vienna. Some Hungarian nobles proposed that Ferdinand, Archduke of Austria (1519–64), who was ruler of neighbouring Austria and tied to Louis II's family by marriage, be King of Hungary, citing previous agreements that the Habsburgs would take the Hungarian throne if Louis died without heirs. However, other nobles turned to the nobleman John Zápolya who, being supported by Suleiman, remained unrecognized by the Christian powers of Europe. In 1541 the Habsburgs once again engaged in conflict with the Ottomans, attempting to lay siege to Buda. With their efforts repulsed, and more Habsburg fortresses captured as a result, Ferdinand and his brother Charles V were forced to conclude a humiliating five-year treaty with Suleiman. Ferdinand renounced his claim to the Kingdom of Hungary and was forced to pay a fixed yearly sum to the Sultan for the Hungarian lands he continued to control. Of more symbolic importance, the treaty referred to Charles V not as 'Emperor', but in rather plainer terms as the 'King of Spain', leading Suleiman to consider himself the true 'Caesar'. With his main European rivals subdued, Suleiman had assured the Ottoman Empire a powerful role in the political landscape of Europe.

As Suleiman stabilized his European frontiers, he now turned his attention to the ever present threat posed by the Shi'a Safavid dynasty of Persia (Iran). Two events in particular were to precipitate a recurrence of tensions. First, Shah Tahmasp had the Baghdad governor loyal to Suleiman killed and replaced with an adherent of the Shah, and second, the governor of Bitlis had defected and sworn allegiance to the Safavids. As a result, in 1533, Suleiman ordered his Grand Vizier Ibrahim Pasha to lead an army into Asia where he retook Bitlis and occupied Tabriz without resistance. Having joined Ibrahim in 1534, Suleiman made a push towards Persia, only to find the Shah sacrificing territory instead of facing a pitched battle, resorting to harassment of the Ottoman army as it proceeded along the harsh interior. When in the following year Suleiman and Ibrahim made a grand entrance into Baghdad, its commander surrendered the city, thereby confirming Suleiman as the leader of the Islamic world and the legitimate successor to the Abbasid Caliphs.

Attempting to defeat the Shah once and for all, Suleiman embarked upon a second campaign in 1548–1549. As in the previous attempt, Tahmasp avoided confrontation with the Ottoman army and instead chose to retreat, torching Armenia in the process and exposing the Ottoman army to the harsh winter of the Caucasus. Suleiman abandoned the campaign with temporary Ottoman gains in Tabriz and the Armenian region of Iran, a lasting presence in the province of Van, and some forts in Georgia. In 1553 Suleiman began his third and final campaign against the Shah. Having initially lost territories in Erzurum to the Shah's son, Suleiman retaliated by recapturing Erzurum, crossing the Upper Euphrates and laying waste to parts of Persia. The Shah's army continued its strategy of avoiding the Ottomans, leading to a stalemate from which neither army made any significant gain. In 1554, a settlement was signed which was to conclude Suleiman's Asian campaigns. It included the return of Tabriz, but secured Baghdad, lower Mesopotamia, the mouths of the river Euphrates and Tigris, as well as part of the Persian Gulf. The Shah also promised to cease all raids into Ottoman territory.

In the Indian Ocean, Suleiman led several naval campaigns against the Portuguese in an attempt to remove them and reestablish trade with India. Aden in Yemen was captured by the Ottomans in 1538, in order to provide an Ottoman base for raids against Portuguese possessions on the western coast of India. Sailing on to India, the Ottomans failed against the Portuguese at the Siege of Diu in September 1538, but then returned to Aden where they fortified the city with 100 pieces of artillery. From this base, Sulayman Pasha managed to take control of the whole country of Yemen, also taking Sa'na. Aden arose against the Ottomans however and invited the Portuguese instead, so that the Portuguese were in control of the city until its seizure by Piri Reis in the Capture of Aden (1548). With its strong control of the Red Sea, Suleiman successfully managed to dispute control of the Indian trade routes to the Portuguese and maintained a significant level of trade with the Indian continent throughout the 16th century.

In 1564, Suleiman received an embassy from Aceh (modern Indonesia), requesting Ottoman support against the Portuguese. As a result an Ottoman expedition to Aceh was launched, which was able to provide extensive military support to the Acehnese.

Having consolidated his conquests on land, Suleiman was greeted with the news that the fortress of Koroni in Morea (the modern Peloponnese) had been lost to Charles V's admiral, Andrea Doria. The presence of the Spanish in the Eastern Mediterranean concerned Suleiman, who saw it as an early indication of Charles V's intention to rival Ottoman dominance in the region. Recognizing the need to reassert the navy's preeminence in the Mediterranean, Suleiman appointed an exceptional naval commander in the form of Khair ad Din, known to Europeans as Barbarossa. Once appointed admiral-in-chief, Barbarossa was charged with rebuilding the Ottoman fleet, to such an extent that the Ottoman navy equalled in number those of all other Mediterranean countries put together. In 1535 Charles V won an important victory against the Ottomans at Tunis, which together with the war against Venice the following year, led Suleiman to accept proposals from Francis I of France to form an alliance against Charles. In 1538, the Spanish fleet was defeated by Barbarossa at the Battle of Preveza, securing the eastern Mediterranean for the Turks for 33 years until the defeat at the Battle of Lepanto in 1571.

East of Morocco, huge territories in North Africa were annexed. The Barbary States of Tripolitania, Tunisia, and Algeria became autonomous provinces of the Empire, serving as the leading edge of Suleiman's conflict with Charles V, whose attempt to drive out the Turks failed in 1541. The piracy carried on thereafter by the Barbary pirates of North Africa can be seen in the context of the wars against Spain. For a short period Ottoman expansion secured naval dominance in the Mediterranean. Ottoman navies also controlled the Red Sea, and held the Persian Gulf until 1554, when their ships were defeated by the navy of the Portuguese Empire. The Portuguese had taken Ormus (in the Strait of Hormuz) in 1515 and would continue to vie with Suleiman's forces for control of Aden, in present-day Yemen.

In 1542, facing a common Habsburg enemy, Francis I sought to renew the Franco-Ottoman alliance. As a result, Suleiman dispatched 100 galleys under Barbarossa to assist the French in the western Mediterranean. Barbarossa pillaged the coast of Naples and Sicily before reaching France where Francis made Toulon the Ottoman admirals naval headquarters. The same campaign had seen Barbarossa attack and capture Nice in 1543. By 1544, a peace between Francis I and Charles V had put a temporary end to the alliance between France and the Ottoman Empire.

Elsewhere in the Mediterranean, when the Knights Hospitallers were re-established as the Knights of Malta in 1530, their actions against Muslim navies quickly drew the ire of the Ottomans who assembled another massive army in order to dislodge the Knights from Malta. The Ottomans invaded in 1565, undertaking the Great Siege of Malta, which began on May 18 and lasted until September 8, and is portrayed vividly in the frescoes of Matteo Perez d'Aleccio in the Hall of St. Michael and St. George. At first it seemed that this would be a repeat of the battle on Rhodes, with most of Malta's cities destroyed and half the Knights killed in battle; but a relief force from Spain entered the battle, resulting in the loss of 30,000 Ottoman troops.

Whilst Sultan Suleiman was known as "the Magnificent" in the West, he was always Kanuni Suleiman or "The Lawgiver" to his own Ottoman subjects. As the historian Lord Kinross notes, "Not only was he a great military campaigner, a man of the sword, as his father and great-grandfather had been before him. He differed from them in the extent to which he was also a man of the pen. He was a great legislator, standing out in the eyes of his people as a high-minded sovereign and a magnanimous exponent of justice". The overriding law of the empire was the Shari'ah, or Sacred Law, which as the divine law of Islam was outside of the Sultan's powers to change. Yet an area of distinct law known as the Kanuns (canonical legislation) was dependent on Suleiman's will alone, covering areas such as criminal law, land tenure and taxation. He collected all the judgments that had been issued by the nine Ottoman Sultans who preceded him. After eliminating duplications and choosing between contradictory statements, he issued a single legal code, all the while being careful not to violate the basic laws of Islam. It was within this framework that Suleiman, supported by his Grand Mufti Ebussuud, sought to reform the legislation to adapt to a rapidly changing empire. When the Kanun laws attained their final form, the code of laws became known as the kanun‐i Osmani, or the "Ottoman laws". Suleiman's legal code was to last more than three hundred years.

Suleiman gave particular attention to the plight of the rayas, Christian subjects who worked the land of the Sipahis. His Kanune Raya, or "Code of the Rayas", reformed the law governing levies and taxes to be paid by the rayas, raising their status above serfdom to the extent that Christian serfs would migrate to Turkish territories to benefit from the reforms. The Sultan also played a role in protecting the Jewish subjects of his empire for centuries to come. In late 1553 or 1554, on the suggestion of his favorite doctor and dentist, the Spanish Jew Moses Hamon, the Sultan issued a firman formally denouncing blood libels against the Jews. Furthermore, Suleiman enacted new criminal and police legislation, prescribing a set of fines for specific offences, as well as reducing the instances requiring death or mutilation. In the area of taxation, taxes were levied on various goods and produce, including animals, mines, profits of trade, and import-export duties. In addition to taxes, officials who had fallen into disrepute were likely to have their land and property confiscated by the Sultan.

Education was another important area for the Sultan. Schools attached to mosques and funded by religious foundations provided a largely free education to Muslim boys in advance of the Christian countries of the time. In his capital, Suleiman increased the number of mektebs (primary schools) to fourteen, teaching children to read and write as well as the principles of Islam. Children wishing further education could proceed to one of eight medreses (colleges), whose studies included grammar, metaphysics, philosophy, astronomy, and astrology. Higher medreses provided education of university status, whose graduates became imams or teachers. Educational centers were often one of many buildings surrounding the courtyards of mosques, others included libraries, refectories, fountains, soup kitchens and hospitals for the benefit of the public.

Under Suleiman's patronage, the Ottoman empire entered the golden age of its cultural development. Hundreds of imperial artistic societies (called the Ehl-i Hiref, "Community of the Talented") were administered at the Imperial seat, the Topkapı Palace. After an apprenticeship, artists and craftsmen could advance in rank within their field and were paid commensurate wages in quarterly annual installments. Payroll registers that survive testify to the breadth of Suleiman's patronage of the arts, the earliest of documents dating from 1526 list 40 societies with over 600 members. The Ehl-i Hiref attracted the empire's most talented artisans to the Sultan's court, both from the Islamic world and recently conquered territories in Europe, resulting in a blend of Islamic, Turkish and European cultures. Artisans in service of the court included painters, book binders, furriers, jewellers and goldsmiths. Whereas previous rulers had been influenced by Persian culture (Suleiman's father, Selim I, wrote poetry in Persian), Suleiman's patronage of the arts had seen the Ottoman Empire assert its own artistic legacy.

Suleiman himself was an accomplished poet, writing in Persian and Turkish under the nom de plume Muhibbi (Lover). Some of Suleiman's verses have become Turkish proverbs, such as the well-known Everyone aims at the same meaning, but many are the versions of the story. When his young son Mehmed died in 1543, he composed a moving chronogram to commemorate the year: Peerless among princes, my Sultan Mehmed. In addition to Suleiman's own work, many great talents enlivened the literary world during Suleiman's rule, including Fuzuli and Baki. The literary historian E.J.W. Gibb observed that "at no time, even in Turkey, was greater encouragement given to poetry than during the reign of this Sultan".

Suleiman also became renowned for sponsoring a series of monumental architectural developments within his empire. The Sultan sought to turn Istanbul into the center of Islamic civilization by a series of projects, including bridges, mosques, palaces and various charitable and social establishments. The greatest of these were built by the Sultan's chief architect, Mimar Sinan, under whom Ottoman architecture reached its zenith. Sinan became responsible for over three hundred monuments throughout the empire, including his two masterpieces, the Süleymaniye and Selimiye mosques — the latter built in Edirne in the reign of Suleiman's son Selim II. Suleiman also restored the Dome of the Rock in Jerusalem and the Jerusalem city walls (which are the current walls of the Old City of Jerusalem), renovated the Kaaba in Mecca, and constructed a complex in Damascus.

Suleiman was infatuated with Hürrem Sultan, a harem girl of Ruthenian origin. In the West foreign diplomats, taking notice of the palace gossip about her, called her "Russelazie" or "Roxelana", referring to her Slavic origins. The daughter of an Orthodox Ukrainian priest, she was enslaved and rose through the ranks of the Harem to become Suleiman's favourite. Breaking with two centuries of Ottoman tradition, a former concubine had thus become the legal wife of the Sultan, much to the astonishment of observers in the palace and the city. He also allowed Hürrem Sultan to remain with him at court for the rest of her life, breaking another tradition — that when imperial heirs came of age, they would be sent along with the imperial concubine who bore them to govern remote provinces of the Empire, never to return unless their progeny succeeded to the throne. Under his pen name, Muhibbi, Suleiman composed this poem for Roxelana:

"Throne of my lonely niche, my wealth, my love, my moonlight.
My most sincere friend, my confidant, my very existence, my Sultan, my one and only love.
The most beautiful among the beautiful…
My springtime, my merry faced love, my daytime, my sweetheart, laughing leaf…
My plants, my sweet, my rose, the one only who does not distress me in this world…
My Istanbul, my Caraman, the earth of my Anatolia
My Badakhshan, my Baghdad and Khorasan
My woman of the beautiful hair, my love of the slanted brow, my love of eyes full of mischief…
I'll sing your praises always
I, lover of the tormented heart, Muhibbi of the eyes full of tears, I am happy."

Pargalı İbrahim Pasha was the boyhood friend of Suleiman. Ibrahim was originally Greek Orthodox and when young was educated at the Palace School under the devshirme system. Suleiman made him the royal falconer, then promoted him to first officer of the Royal Bedchamber. Ibrahim Pasha rose to Grand Vizier in 1523 and commander-in-chief of all the armies. Suleiman also conferred upon Ibrahim Pasha the honor of beylerbey of Rumelia, granting Ibrahim authority over all Turkish territories in Europe, as well as command of troops residing within them in times of war. According to a 17th century chronicler, Ibrahim had asked Suleiman not to promote him to such high positions, fearing for his safety; to which Suleiman replied that under his reign no matter what the circumstance, Ibrahim would never be put to death. Yet Ibrahim eventually fell from grace with the Sultan. During his thirteen years as Grand Vizier, his rapid rise to power and vast accumulation of wealth had made Ibrahim many enemies among the Sultan's court. Reports had reached the Sultan of Ibrahim's impudence during a campaign against the Persian Safavid empire: in particular his adoption of the title serasker sultan was seen as a grave affront to Suleiman. Suleiman's suspicion of Ibrahim was worsened by a quarrel between the latter and the Minister of Finance Iskender Chelebi. The dispute ended in the disgrace of Chelebi on charges of intrigue, with Ibrahim convincing Suleiman to sentence the Minister to death. Before his death however, Chelebi's last words were to accuse Ibrahim of conspiracy against the Sultan. These dying words convinced Suleiman of Ibrahim's disloyalty, and on 15 March 1536 Ibrahim's lifeless body was discovered in the Topkapi Palace.

Suleiman's two wives had borne him eight sons, four of whom survived past the 1550s. They were Mustafa, Selim, Bayezid, and Jihangir. Of these, only Mustafa was not Hürrem Sultan's son, but rather Mahidevran Gülbahar Sultan's ("Rose of Spring"), and therefore preceded Hürrem's children in the order of succession. Hürrem was aware that should Mustafa become Sultan her own children would be strangled. Yet Mustafa was recognised as the most talented of all the brothers and was supported by Pargalı İbrahim Pasha, who was by this time Suleiman's Grand Vizier. The Austrian ambassador Busbecq would note "Suleiman has among his children a son called Mustafa, marvellously well educated and prudent and of an age to rule, since he is 24 or 25 years old; may God never allow a Barbary of such strength to come near us", going on to talk of Mustafa's "remarkable natural gifts".

Hürrem is usually held at least partly responsible for the intrigues in nominating a successor. Although she was Suleiman's wife, she exercised no official public role as her contemporary in England, Anne Boleyn, had done. This did not, however, prevent Hürrem from wielding powerful political influence. Since the Empire lacked any formal means of nominating a successor, succession usually involved the death of competing princes in order to avert civil unrest and rebellions. In attempting to avoid the execution of her sons, Hürrem used her influence to eliminate those who supported Mustafa's accession to the throne. Thus in power struggles apparently instigated by Hürrem, Suleiman had Ibrahim murdered and replaced with her sympathetic son-in-law, Rustem Pasha. By 1552, when the campaign against Persia had begun with Rustem appointed commander-in-chief of the expedition, intrigues against Mustafa began. Rustem sent one of Suleiman's most trusted men to report that since Suleiman was not at the head of the army, the soldiers thought the time had come to put a younger prince on the throne; at the same time he spread rumors that Mustafa had proved receptive to the idea.

Angered by what he came to believe were Mustafa's plans to claim the throne, the following summer upon return from his campaign in Persia, Suleiman summoned him to his tent in the Ereğli valley, stating he would "be able to clear himself of the crimes he was accused of and would have nothing to fear if he came". Mustafa was confronted with a choice: either he appeared before his father at the risk of being killed; or, if he refused to attend, he would be accused of betrayal. In the end, Mustafa chose to enter his father's tent, confident that the support of the army would protect him. Busbecq, who claims to have received an account from an eyewitness, describes Mustafa's final moments. As Mustafa entered his father's tent, Suleiman's Eunuchs attacked Mustafa, with the young prince putting up a brave defence. Suleiman, separated from the struggle only by the linen hangings of the tent, peered through the chamber of his tent and "directed fierce and threatening glances upon the mutes, and by menacing gestures sternly rebuked their hesitation. Thereupon, the mutes in their alarm, redoubling their efforts, hurled Mustafa to the ground and, throwing the bowstring round his neck, strangled him."

Jihangir is said to have died of grief a few months after the news of his half-brother's murder. The two surviving brothers, Bayezid and Selim, were given command in different parts of the empire. Within a few years, however, civil war broke out between the brothers, each supported by his loyal forces. With the aid of his father's army, Selim defeated Bayezid in Konya in 1559, leading the latter to seek refuge with the Persians along with his four sons. Following diplomatic exchanges, the Sultan demanded from the Persian Shah that Bayezid be either extradited or executed. In return for large amounts of gold, the Shah allowed a Turkish executioner to strangle Bayezid and his four sons in 1561, clearing the path for Selim's succession to the throne seven years later. On 5/6 September 1566, Suleiman, who had set out from Istanbul to command an expedition to Hungary, died before an Ottoman victory at the Battle of Szigetvár in Hungary.