Haile Selassie I ("Power of the Trinity") (23 July 1892 – 27 August 1975), born Tafari Makonnen, was Ethiopia's regent from 1916 to 1930 and Emperor of Ethiopia from 1930 to 1974. The heir to a dynasty that traced its origins to the 13th century, and from there by tradition back to King Solomon and the Queen of Sheba, Haile Selassie is a defining figure in both Ethiopian and African history.

At the League of Nations in 1936, the Emperor condemned the use of chemical weapons by Italy against his people. His internationalist views led to Ethiopia becoming a charter member of the United Nations, and his political thought and experience in promoting multilateralism and collective security have proved seminal and enduring. His suppression of rebellions among the nobles (mekwannint), as well as what some perceived to be Ethiopia's failure to modernize adequately, earned him criticism among some contemporaries and historians. Haile Selassie is revered as God incarnate among the Rastafari movement, the number of followers is estimated between 200,000 and 800,000. Begun in Jamaica in the 1930s, the Rastafarian movement perceives Haile Selassie as a messianic figure who will lead the peoples of Africa and the African diaspora to a golden age of peace, righteousness, and prosperity.

Haile Selassie was born Tafari Makonnen. He would later become Ras Tafari Makonnen; "Ras" translates literally to "head" and is the equivalent of "duke", though it is often rendered in translation as "prince". In 1928, he was elevated to Negus, "King".

Upon his ascension to Emperor in 1930, he took the name Haile Selassie, meaning "Power of the Trinity". Haile Selassie's full title in office was "His Imperial Majesty Haile Selassie I, King of Kings, Lord of Lords, Conquering Lion of the Tribe of Judah, and Elect of God". This title reflects Ethiopian dynastic traditions, which hold that all monarchs must trace their lineage back to Menelik I, who in the Ethiopian tradition was the offspring of King Solomon and the Queen of Sheba. To Ethiopians Haile Selassie has been known by many names, including Janhoy, Talaqu Meri, and Abba Tekel. The Rastafari employ many of these appellations, also referring to him as HIM, Jah, and Jah Rastafari.

Haile Selassie I was born Tafari Makonnen from a mixed Oromo, Amhara, and Gurage family on 23 July 1892, in the village of Ejersa Goro, in the Harar province of Ethiopia. His mother was Woizero ("Lady") Yeshimebet Ali Abajifar, daughter of the renowned Oromo ruler of Wollo province Dejazmach Ali Abajifar. Haile Selassie's father was Ras Makonnen Woldemikael Gudessa, the governor of Harar; Ras Makonnen served as a general in the First Italo–Ethiopian War, playing a key role at the Battle of Adwa. He inherited his imperial blood through his paternal grandmother, Princess Tenagnework Sahle Selassie, who was an aunt of Emperor Menelik II, and as such asserted direct descent from Makeda, the Queen of Sheba, and King Solomon of ancient Israel. Ras Makonnen arranged for Tafari as well as his first cousin, Ras Imru Haile Selassie to receive instruction in Harar from Abba Samuel Wolde Kahin, an Ethiopian capuchin monk, and from Dr. Vitalien, a surgeon from Guadeloupe. Tafari was named Dejazmach (literally "commander of the gate", roughly equivalent to "count") at the age of 13, on 1 November 1905. Shortly thereafter, his father Ras Makonnen died at Kulibi, in 1906.

Tafari assumed the titular governorship of Selale in 1906, a realm of marginal importance but one that enabled him to continue his studies. In 1907, he was appointed governor over part of the province of Sidamo. It is alleged that during his late teens, Haile Selassie was married to Woizero Altayech, and that from this union, his daughter Romanework Haile Selassie was born. Following the death of his brother Yelma in 1907, the governorate of Harar was left vacant, and its administration was left to Menelik's loyal general, Dejazmach Balcha Safo. Balcha Safo's administration of Harar was ineffective, and so during the last illness of Menelik II, and the brief reign of Empress Taitu Bitul, Tafari was made governor of Harar in 1910 or 1911. On 3 August he married Menen Asfaw of Ambassel, niece of heir to the throne Lij Iyasu. The extent to which Tafari Makonnen contributed to the movement that would come to depose Iyasu V is unclear. Iyasu V, or Lij Iyasu, was the designated but uncrowned Emperor of Ethiopia from 1913 to 1916. Iyasu's reputation for scandalous behavior and a disrespectful attitude towards the nobles at the court of his grandfather, Menelik II, damaged his reputation. His flirtation with Islam was considered treasonous among the Ethiopian Orthodox Christian leadership of the empire. On 27 September 1916, Iyasu was deposed.

Contributing to the movement that deposed Iyasu were conservatives such as Fitawrari Habte Giyorgis, Menelik II's longtime Minister of War. The movement to depose Iyasu preferred Tafari, as he attracted support from both progressive and conservative factions. Ultimately, Iyasu was deposed on the grounds of conversion to Islam. In his place, the daughter of Menelik II (the aunt of Iyasu) was named Empress Zewditu and made Regent for Tafari during his minority. Tafari was elevated to the rank of Ras and was made heir apparent and Crown Prince. In the power arrangement that followed, Tafari accepted the role of Regent Plenipotentiary (Balemulu 'Inderase) and became the de facto ruler of the Ethiopian Empire (Mangista Ityop'p'ya). Zewditu would govern while Tafari would administer. While Iyasu had been deposed on 27 September 1916, on 8 October the coup d'etat went awry. Iyasu managed to escape into the Ogaden Desert and his father, Negus Mikael of Wollo, had time to come to his aid. On 27 October, Negus Mikael and his army met an army under Fitawrari Habte Giyorgis loyal to Zewditu and Tafari. During the Battle of Segale, Negus Mikael was defeated and captured. Any chance that Iyasu would regain the throne was ended and he went into hiding. On 11 January 1921, after avoiding capture for about five years, Iyasu was taken into custody by Gugsa Araya Selassie.

On 11 February 1917, the coronation for Zewditu took place. She pledged to rule justly through her Regent, Tafari. While Tafari was the more visible of the two, Zewditu was far from an honorary ruler. Her position required that she arbitrate the claims of competing factions. In other words, she had the last word. Tafari carried the burden of daily administration but, because his position was relatively weak, this was often an exercise in futility for him. Initially his personal army was poorly equipped, his finances were limited, and he had little leverage to withstand the combined influence of the Empress, the Minister of War, or the provincial governors. During his Regency, the new Crown Prince developed the policy of cautious modernization initiated by Menelik II. He secured Ethiopia's admission to the League of Nations in 1923 by promising to eradicate slavery; each emperor since Tewodros II had issued proclamations to halt slavery, but without effect: the internationally scorned practice persisted well into Haile Selassie's reign.

In 1924, Ras Tafari toured Europe and the Middle East visiting Jerusalem, Cairo, Alexandria, Brussels, Amsterdam, Stockholm, London, Geneva, and Athens. With him on his tour was a group that included Ras Seyum Mangasha of western Tigre Province, Ras Hailu Tekle Haymanot of Gojjam Province, Ras Mulugeta Yeggazu of Illubabor Province, Ras Makonnen Endelkachew, and Blattengeta Heruy Welde Sellase. The primary goal of the trip to Europe was for Ethiopia to gain access to the sea. In Paris, Tafari was to find out from the French Foreign Ministry (Quai d'Orsay) that this goal would not be realized. However, failing this, he and his retinue inspected schools, hospitals, factories, and churches. Although patterning many reforms after European models, Tafari remained wary of European pressure. To guard against economic imperialism, Tafari required that all enterprises have at least partial local ownership. Of his modernization campaign, he remarked, "We need European progress only because we are surrounded by it. That is at once a benefit and a misfortune." Throughout Ras Tafari's travels in Europe, the Levant, and Egypt, he and his entourage were greeted with enthusiasm and fascination. He was accompanied by Seyum Mangasha and Hailu Tekle Haymanot who, like Tafari, were sons of generals who contributed to the victorious war against Italy a quarter century earlier at the Battle of Adwa. Another member of his entourage, Mulugeta Yeggazu, actually fought at Adwa as a young man. The "Oriental Dignity" of the Ethiopians and their "rich, picturesque court dress" were sensationalized in the media; among his entourage he even included a pride of lions, which he distributed as gifts to President Alexandre Millerand and Prime Minister Raymond Poincaré of France, to King George V of the United Kingdom, and to the Zoological Garden (Jardin Zoologique) of Paris. As one historian noted, "Rarely can a tour have inspired so many anecdotes". In return for two lions, the United Kingdom presented Ras Tafari with the imperial crown of Emperor Tewodros II for its safe return to Empress Zewditu. The crown had been taken by Robert Napier during the 1868 Expedition to Abyssinia. In this period, the Crown Prince visited the Armenian monastery of Jerusalem. There, he adopted 40 Armenian orphans who had escaped the Armenian genocide of the Ottoman Empire. Ras Tafari arranged for the musical education of the youths, and they came to form the imperial brass band.

In 1928, the authority of Ras Tafari Makonnen was challenged when Dejazmatch Balcha Safo went to Addis Ababa with a sizeable armed force. When Tafari consolidated his hold over the provinces, many of Menilek's appointees refused to abide by the new regulations. Balcha Safo, Governor (Shum) of coffee-rich Sidamo Province was particularly troublesome. The revenues he remitted to the central government did not reflect the accrued profits and Tafari recalled him to Addis Ababa. The old man came in high dudgeon and, insultingly, with a large army. The Dejazmatch paid homage to Empress Zewditu, but snubbed Ras Tafari. On 18 February, while Balcha Safo and his personal bodyguard were in Addis Ababa, Ras Tafari had Ras Kassa Haile Darge bought off his army and arranged to have him displaced as the Shum of Sidamo Province by Birru Wolde Gabriel who himself was replaced by Desta Damtew. Even so, the gesture of Balcha Safo empowered Empress Zewditu politically and she attempted to have Tafari tried for treason. He was tried for his benevolent dealings with Italy including a 20-year peace accord which was signed on 2 August. In September, a group of palace reactionaries including some of the courtiers of the Empress, made a final bid to get rid of Tafari. The attempted coup d'état was tragic in its origins and comic in its end. When confronted by Tafari and a company of his troops, the ringleaders of the coup took refuge on the palace grounds in Menilek's mausoleum. Tafari and his men surrounded them only to be surrounded themselves by the personal guard of Zewditu. More of Tafari's khaki clad soldiers arrived and, with superiority of arms, decided the outcome in his favor. Popular support, as well as the support of the police, remained with Tafari. Ultimately, the Empress relented and, on 7 October 1928, she crowned Tafari as Negus (Amharic: "King").

The crowning of Tafari as King was controversial. He occupied the same territory as the Empress rather than going off to a regional kingdom of the empire. Two monarchs, even with one being the vassal and the other the Emperor (in this case Empress), had never occupied the same location as their seat in Ethiopian history. Conservatives agitated to redress this perceived insult to the dignity of the crown, leading to the rebellion of Ras Gugsa Welle. Gugsa Welle was the husband of the Empress and the Shum of Begemder Province. In early 1930, he raised an army and marched it from his governorate at Gondar towards Addis Ababa. On 31 March 1930, Gugsa Welle was met by forces loyal to Negus Tafari and was defeated at the Battle of Anchem. Gugsa Welle was killed in action. News of Gugsa Welle's defeat and death had hardly spread through Addis Ababa when the Empress died suddenly on 2 April 1930. Although it was long rumored that the Empress was poisoned upon the defeat of her husband, or alternately that she died from shock upon hearing of the death of her estranged yet beloved husband, it has since been documented that the Empress succumbed to a flu-like fever and complications from diabetes.

With the passing of Zewditu, Tafari himself rose to Emperor and was proclaimed Neguse Negest ze-'Ityopp'ya, "King of Kings of Ethiopia". He was crowned on 2 November 1930, at Addis Ababa's Cathedral of St. George. The coronation was by all accounts "a most splendid affair", and it was attended by royals and dignitaries from all over the world. Among those in attendance were George V's son Prince Henry, Marshal Franchet d' Esperey of France, and the Prince of Udine representing Italy. Emissaries from the United States, Egypt, Turkey, Sweden, Belgium, and Japan were also present. British author Evelyn Waugh was also present, penning a contemporary report on the event. One newspaper report suggested that the celebration may have incurred a cost in excess of $3,000,000. Many of those in attendance received lavish gifts; in one instance, the Christian Emperor even sent a gold-encased Bible to an American bishop who had not attended the coronation, but who had dedicated a prayer to the Emperor on the day of the coronation.

Haile Selassie introduced Ethiopia's first written constitution on 16 July 1931, providing for a bicameral legislature. The constitution kept power in the hands of the nobility, but it did establish democratic standards among the nobility, envisaging a transition to democratic rule: it would prevail "until the people are in a position to elect themselves." The constitution limited the succession to the throne to the descendants of Haile Selassie, a point that met with the disapprobation of other dynastic princes, including the princes of Tigrai and even the Emperor's loyal cousin, Ras Kassa Haile Darge. In 1932, the Kingdom of Jimma was formally absorbed into Ethiopia following the death of King Abba Jifar II of Jimma.

Ethiopia became the target of renewed Italian imperialist designs in the 1930s. Benito Mussolini's fascist regime was keen to avenge the military defeats Italy had suffered to Ethiopia in the First Italo-Abyssinian War, and to efface the failed attempt by "liberal" Italy to conquer the country, as epitomised by the defeat at Adowa. A conquest of Ethiopia could also empower the cause of fascism and embolden its rhetoric of empire. Ethiopia would also provide a bridge between Italy's Eritrean and Italian Somaliland possessions. Ethiopia's position in the League of Nations did not dissuade the Italians from invading in 1935; the "collective security" envisaged by the League proved useless, and a scandal erupted when the Hoare-Laval Pact revealed that Ethiopia's League allies were scheming to appease Italy. Following the 1935 Italian invasion of Ethiopia, Haile Selassie joined his northern armies and set up headquarters at Desse in Wollo province. He issued his famous mobilization order on 3 October 1935. On 19 October 1935, Haile Selassie gave more precise orders for his army to his Commander-in-Chief, Ras Kassa. Compared to the Ethiopians, the Italians had an advanced, modern military which included a large air force. The Italians would also come to employ chemical weapons extensively throughout the conflict, even targeting Red Cross field hospitals in violation of the Geneva Convention. On 6 October, Italian honor was avenged when Adwa fell. But, by November, the pace of invasion had slowed appreciably and Haile Selassie's northern armies were able to launch what was known as the "Christmas Offensive". During this offensive, the Italians were forced back in places and put on the defensive. However, by early in 1936, the First Battle of Tembien stopped the progress of the Ethiopian offensive and the Italians were ready to continue their offensive. Following the defeat and destruction of the northern Ethiopian armies at the Battle of Amba Aradam, the Second Battle of Tembien, and the Battle of Shire, Haile Selassie took the field with the last Ethiopian army on the northern front. On 31 March 1936, he launched a counterattack against the Italians himself at the Battle of Maychew in southern Tigray. The Emperor's army was defeated and retreated in disarray. As Haile Selassie's army withdrew, the Italians attacked from the air along with rebellious Raya and Azebo tribesmen on the ground, who were armed and paid by the Italians. Haile Selassie made a solitary pilgrimage to the churches at Lalibela, at considerable risk of capture, before returning to his capital. After a stormy session of the council of state, it was agreed that because Addis Ababa could not be defended, the government would relocate to the southern town of Gore, and that in the interest of preserving the Imperial house, the Emperor's wife Menen Asfaw and the rest of the Imperial family should immediately depart for Djibouti, and from there continue on to Jerusalem. After further debate as to whether Haile Selassie should go to Gore or accompany his family into exile, it was agreed that Haile Selassie should leave Ethiopia with his family and present the case of Ethiopia to the League of Nations at Geneva. The decision was not unanimous and several participants, including the nobleman Page (Blatta) Tekle Wolde Hawariat, objected to the idea of an Ethiopian monarch fleeing before an invading force. Haile Selassie appointed his cousin Ras Imru Haile Selassie as Prince Regent in his absence, departing with his family for Djibouti on 2 May 1936.

On 5 May, Marshal Pietro Badoglio led Italian troops into Addis Ababa, and Mussolini declared Ethiopia an Italian province. Victor Emanuel III was proclaimed as the new Emperor of Ethiopia. However, on the previous day, the Ethiopian exiles had left Djibouti aboard the British cruiser HMS Enterprise. They were bound for Jerusalem in the British Mandate of Palestine, where the Ethiopian royal family maintained a residence. The Imperial family disembarked at Haifa and then went on to Jerusalem. Once there, Haile Selassie and his retinue prepared to make their case at Geneva. The choice of Jerusalem was highly symbolic, since the Solomonic Dynasty claimed descent from the House of David. Leaving the Holy Land, Haile Selassie and his entourage sailed for Gibraltar aboard the British cruiser HMS Capetown. From Gibraltar, the exiles were transferred to an ordinary liner. By doing this, the government of the United Kingdom was spared the expense of a state reception. Mussolini, upon invading Ethiopia, had promptly declared his own "Italian Empire"; because the League of Nations afforded Haile Selassie the opportunity to address the assembly, Italy even withdrew its League delegation, on 12 May 1936. It was in this context that Haile Selassie walked into the hall of the League of Nations, introduced by the President of the Assembly as "His Imperial Majesty, the Emperor of Ethiopia" (Sa Majesté Imperiale, l' Empereur d' Ethiopie). The introduction caused a great many Italian journalists in the galleries to erupt into jeering, heckling, and whistling. As it turned out, they had earlier been issued whistles by Mussolini's son-in-law, Count Galeazzo Ciano. Haile Selassie waited calmly for the hall to be cleared, and responded "majestically" with a speech sometimes considered among the most stirring of the 20th century. Although fluent in French, the working language of the League, Haile Selassie chose to deliver his historic speech in his native Amharic. He asserted that, because his "confidence in the League was absolute", his people were now being slaughtered. He pointed out that the same European states that found in Ethiopia's favor at the League of Nations were refusing Ethiopia credit and war matériel while aiding Italy, which was employing chemical weapons on military and civilian targets alike. Noting that his own "small people of 12 million inhabitants, without arms, without resources" could never withstand an attack by a large power such as Italy, with its 42 million people and "unlimited quantities of the most death-dealing weapons", he contended that all small states were threatened by the aggression, and that all small states were in effect reduced to vassal states in the absence of collective action. He admonished the League that "God and history will remember your judgment." It is collective security: it is the very existence of the League of Nations. It is the confidence that each State is to place in international treaties... In a word, it is international morality that is at stake. Have the signatures appended to a Treaty value only in so far as the signatory Powers have a personal, direct and immediate interest involved?

The speech made the Emperor an icon for anti-Fascists around the world, and Time Magazine named him "Man of the Year". He failed, however, to get what he most needed: the League agreed to only partial and ineffective sanctions on Italy, and several members even recognized the Italian conquest. Haile Selassie spent his exile years (1936–1941) in Bath, United Kingdom, in Fairfield House, which he bought. The Emperor and Ras Kassa took morning walks together behind the high walls of the 14-room Georgian house. Haile Selassie's favorite reading was "diplomatic history." But most of his serious hours were occupied with the 90,000-word story of his life which he was laboriously writing in Amharic. Prior to Fairfield House, he briefly stayed at Warne's Hotel in Worthing and in Parkside, Wimbledon. A bust of Haile Selassie is in nearby Cannizaro Park to commemorate this time and is a popular place of pilgrimage for London's Rastafarian community. Haile Selassie's activity in this period was focused on countering Italian propaganda as to the state of Ethiopian resistance and the legality of the occupation. He spoke out against the desecration of houses of worship and historical artifacts (including the theft of a 1,600-year old imperial obelisk), and condemned the atrocities suffered by the Ethiopian civilian population. He continued to plead for League intervention and to voice his certainty that "God's judgment will eventually visit the weak and the mighty alike", though his attempts to gain support for the struggle against Italy were largely unsuccessful until Italy entered World War II on the German side in June 1940.

The Emperor's pleas for international support did take root in the United States, particularly among African American organizations sympathetic to the Ethiopian cause. In 1937, Haile Selassie was to give a Christmas Day radio address to the American people to thank his supporters when his taxi was involved in a traffic accident, leaving him with a fractured knee. Rather than canceling the radio appearance, he proceeded in much pain to complete the address, in which he linked Christianity and goodwill with the Covenant of the League of Nations, and asserted that "War is not the only means to stop war". During this period, Haile Selassie suffered several personal tragedies. His two sons-in-law, Ras Desta Damtew and Dejazmach Beyene Merid, were both executed by the Italians. The Emperor's daughter, Princess Romanework, wife of Dejazmach Beyene Merid, was herself taken into captivity with her children, and she died in Italy in 1941. His daughter Tsehai died during childbirth shortly after the restoration in 1942.

After his return to Ethiopia, he donated Fairfield House to the city of Bath as a residence for the aged, and it remains so to this day. British forces, which consisted primarily of Ethiopian-backed African and South African colonial troops under the "Gideon Force" of Colonel Orde Wingate, coordinated the military effort to liberate Ethiopia. The Emperor himself issued several imperial proclamations in this period, demonstrating that, while authority was not divided up in any formal way, British military might and the Emperor's populist appeal could be joined in the concerted effort to liberate Ethiopia. On 18 January 1941, during the East African Campaign, Haile Selassie crossed the border between Sudan and Ethiopia near the village of Um Iddla. The standard of the Lion of Judah was raised again. Two days later, he and a force of Ethiopian patriots joined Gideon Force which was already in Ethiopia and preparing the way. Italy was defeated by a force of the United Kingdom, the Commonwealth of Nations, Free France, Free Belgium, and Ethiopian patriots. On 5 May 1941, Haile Selassie entered Addis Ababa and personally addressed the Ethiopian people, five years to the day since his 1936 exile.

After World War II, Ethiopia became a charter member of the United Nations. In 1948, the Ogaden, a region disputed with Somalia, was granted to Ethiopia. On 2 December 1950, the UN General Assembly adopted Resolution 390 (V), establishing the federation of Eritrea (the former Italian colony) into Ethiopia. Eritrea was to have its own constitution, which would provide for ethnic, linguistic, and cultural balance, while Ethiopia was to manage its finances, defense, and foreign policy. Despite his centralization policies that had been made before World War II, Haile Selassie still found himself unable to push for all the programs he wanted. In 1942, he attempted to institute a progressive tax scheme, but this failed due to opposition from the nobility, and only a flat tax was passed; in 1951, he agreed to reduce this as well. Ethiopia was still "semi-feudal", and the Emperor's attempts to alter its social and economic form by reforming its modes of taxation met with resistance from the nobility and clergy, which were eager to resume their privileges in the postwar era. Where Haile Selassie actually did succeed in effecting new land taxes, the burdens were often passed by the landowners to the peasants. Despite his wishes, the tax burden remained primarily on the peasants.

Between 1941 and 1959, Haile Selassie worked to establish the autocephaly of the Ethiopian Orthodox Church. The Ethiopian Orthodox Church had been headed by the abuna, a bishop who answered to the Partriarchate in Egypt. Haile Selassie applied to Egypt's Holy Synod in 1942 and 1945 to establish the independence of Ethiopian bishops, and when his appeals were denied he threatened to sever relations with the See of St. Mark. Finally, in 1959, Pope Kyrillos VI elevated the Abuna to Patriarch-Catholicos. The Ethiopian Church remained affiliated with the Alexandrian Church. In addition to these efforts, Haile Selassie changed the Ethiopian church-state relationship by introducing taxation of church lands, and by restricting the legal privileges of the clergy, who had formerly been tried in their own courts for civil offenses.

In keeping with the principle of collective security, for which he was an outspoken proponent, he sent a contingent under General Mulugueta Bulli, known as the Kagnew Battalion, to take part in the UN Conflict in Korea. It was attached to the American 7th Infantry Division, and fought in a number of engagements including the Battle of Pork Chop Hill. In a 1954 speech, the Emperor spoke of Ethiopian participation in the Korean conflict as a redemption of the principles of collective security.

During the celebrations of his Silver Jubilee in November 1955, Haile Selassie introduced a revised constitution, whereby he retained effective power, while extending political participation to the people by allowing the lower house of parliament to become an elected body. Party politics were not provided for. Modern educational methods were more widely spread throughout the Empire, and the country embarked on a development scheme and plans for modernization, tempered by Ethiopian traditions, and within the framework of the ancient monarchical structure of the state. Haile Selassie compromised when practical with the traditionalists in the nobility and church. He also tried to improve relations between the state and ethnic groups, and granted autonomy to Afar lands that were difficult to control. Still, his reforms to end feudalism were slow and weakened by the compromises he made with the entrenched aristocracy. The Revised Constitution of 1955 has been criticized for reasserting "the indisputable power of the monarch" and maintaining the relative powerlessness of the peasants.

His international fame and acceptance also grew. In 1954 he visited West Germany, becoming the first head of state to do so after the end of World War II. Many elderly Germans still vividly recall the Emperor's visit, as it signaled their acceptance back into the world, as a peaceful nation. He donated blankets produced by the Debre Birhan Blanket Factory, in Ethiopia, to the war-ravaged German people. Haile Selassie contributed Ethiopian troops to the United Nations Operation in the Congo peacekeeping force during the 1960 Congo Crisis, to consolidate Congolese integrity and independence from Belgian troops, per United Nations Security Council Resolution 143.

On 13 December 1960, while Haile Selassie was on a state visit to Brazil, his Imperial Guard forces staged an unsuccessful coup attempt, briefly proclaiming Haile Selassie's eldest son Asfa Wossen as Emperor. The coup d'état was crushed by the regular Army and police forces. The coup attempt lacked broad popular support, was denounced by the Ethiopian Orthodox Church, and was unpopular among the Army, Air and Police forces. Nonetheless, the effort to depose the Emperor had support among students and the educated classes. The coup attempt has been characterized as a pivotal moment in Ethiopian history, the point at which Ethiopians "for the first time questioned the power of the king to rule without the people's consent". Student populations began to empathize with the peasantry and poor, and to advocate on their behalf. The coup spurred Haile Selassie to accelerate reform, which manifested in the form of land grants to military and police officials.

The Emperor continued to be a staunch ally of the West, while pursuing a firm policy of decolonization in Africa, which was still largely under European colonial rule. The United Nations conducted a lengthy inquiry regarding the status of Eritrea, with the superpowers each vying for a stake in the state's future. Britain, the administrator at the time, suggested the partition of Eritrea between Sudan and Ethiopia, separating Christians and Muslims. The idea was instantly rejected by Eritrean political parties, as well as the UN. A UN plebiscite voted 46 to 10 to have Eritrea be federated with Ethiopia, which was later stipulated on 2 December 1950 in resolution 390 (V). Eritrea would have its own parliament and administration and would be represented in what had been the Ethiopian parliament and would become the federal parliament. However, Haile Selassie would have none of European attempts to draft a separate Constitution under which Eritrea would be governed, and wanted his own 1955 Constitution protecting families to apply in both Ethiopia and Eritrea. In 1961 the 30-year Eritrean Struggle for Independence began, followed by Haile Selassie's dissolution of the federation and shutting down of Eritrea's parliament. In 1961, tensions between independence-minded Eritreans and Ethiopian forces culminated in the Eritrean War of Independence. The Emperor declared Eritrea the fourteenth province of Ethiopia in 1962. The war would continue for 30 years, as first Haile Selassie, then the Soviet-backed junta that succeeded him, attempted to retain Eritrea by force.

In 1963, Haile Selassie presided over the establishment of the Organisation of African Unity, with the new organization establishing its headquarters in Addis Ababa. As more African states won their independence, he played an important role as Pan-Africanist, and along with Modibo Keïta of Mali was successful in negotiating the Bamako Accords, which brought an end to the border conflict between Morocco and Algeria. Also in 1963, on October 4, Selassie addressed the General Assembly of the United Nations. On 25 November 1963, the Emperor was among other heads-of-state, including French President Charles de Gaulle, who traveled to Washington D.C. and attended the burial of assassinated American President John F. Kennedy at Arlington National Cemetery.

In 1966, Haile Selassie attempted to create a modern, progressive tax that included registration of land, which would significantly weaken the nobility. Even with alterations, this law led to a revolt in Gojjam, which was repressed although enforcement of the tax was abandoned. The revolt, having achieved its design in undermining the tax, encouraged other landowners to defy Haile Selassie. Student unrest became a regular feature of Ethiopian life in the 1960s and 1970s. Marxism took root in large segments of the Ethiopian intelligentsia, particularly among those who had studied abroad and had thus been exposed to radical and left-wing sentiments that were becoming popular in other parts of the globe. Resistance by conservative elements at the Imperial Court and Parliament, and by the Ethiopian Orthodox Church, made Haile Selassie's land reform proposals difficult to implement, and also damaged the standing of the government, costing Haile Selassie much of the goodwill he had once enjoyed. This bred resentment among the peasant population. Efforts to weaken unions also hurt his image. As these issues began to pile up, Haile Selassie left much of domestic governance to his Prime Minister, Aklilu Habte Wold, and concentrated more on foreign affairs.

Outside of Ethiopia, Haile Selassie continued to enjoy enormous prestige and respect. As the longest serving Head of State in power, Haile Selassie was often given precedence over other leaders at state events, such as the state funerals of John F. Kennedy and Charles de Gaulle, the summits of the Non-Aligned Movement, and the 1971 celebration of the 2,500 years of the Persian Empire. His high profile and frequent travels around the world raised Ethiopia's international image.

Famine mostly in Wollo, northeastern Ethiopia, as well as in some parts of Tigray is estimated to have killed 40,000 to 80,000 Ethiopians between 1972-74. Although the region is infamous for recurrent crop failures and continuous food shortage and starvation risk, this episode was remarkably severe. It led to the 1973 production of the ITV programme The Unknown Famine by Jonathan Dimbleby. Dimbleby's report suggested a far higher death toll than was borne out by the facts, stimulating a massive influx of aid while at the same time destabilizing Haile Selassie's regime. Some reports suggest that the Emperor was unaware of the extent of the famine, while others assert that he was well aware of it. In addition to the exposure of attempts by corrupt local officials to cover up the famine from the Imperial government, the Kremlin's depiction of Haile Selassie's Ethiopia as backwards and inept (relative to the purported utopia of Marxism-Leninism) contributed to the popular uprising that led to its downfall and the rise of Mengistu Haile Mariam. The famine and its image in the media undermined popular support of the government, and Haile Selassie's once unassailable personal popularity fell. The crisis was exacerbated by military mutinies and high oil prices, the latter a result of the 1973 oil crisis. The international economic crisis triggered by the oil crisis caused the costs of imported goods, gasoline, and food to skyrocket, while unemployment spiked. In February 1974, four days of serious riots in Addis against a sudden economic inflation left five dead. The Emperor responded by announcing on national television a rollback of gasoline prices and a freeze on the cost of basic commodities. This calmed the public, but the promised 33% military wage hike was not substantial enough to pacify the army, which then mutinied, beginning in Asmara and spreading throughout the empire. This mutiny led to the resignation of Prime Minister Aklilu Habte Wold on 27 February 1974. Haile Selassie again went on television to agree to the army's demands for still greater pay, and named Endalkatchew Makonnen as his new Prime Minister. However, despite Endalkatchew's many concessions, discontent continued in March with a four-day general strike that paralyzed the nation.

The Derg, a committee of low-ranking military officers and enlisted men, set up in June to investigate the military's demands, took advantage of the government's disarray to depose Haile Selassie on 12 September 1974. General Aman Mikael Andom, a Protestant of Eritrean origin, served briefly as provisional head of state pending the return of Crown Prince Asfa Wossen, who was then receiving medical treatment abroad. Haile Selassie was placed under house arrest briefly at the 4th Army Division in Addis Ababa, while most of his family was detained at the late Duke of Harrar's residence in the north of the capital. The last months of the Emperor's life were spent in imprisonment, in the Grand Palace. Later, most of the Imperial family was imprisoned in the Addis Ababa prison known as "Alem Bekagn", or "I am finished with the world". On 23 November 1974, 60 former high officials of the Imperial government, known as "the Sixty", were executed without trial. The executed included Haile Selassie's grandson and two former Prime Ministers. These killings, known to Ethiopians as "Bloody Saturday", were condemned by Crown Prince Asfa Wossen; the Derg responded to his rebuke by revoking its acknowledgment of his imperial legitimacy, and announcing the end of the Solomonic dynasty.

On 28 August 1975, the state media officially reported publicly that the "ex-monarch" Haile Selassie had died on 27 August of "respiratory failure" following complications from a prostate operation. His doctor, Asrat Woldeyes, denied that complications had occurred and rejected the government version of his death. Some imperial loyalists believed that the Emperor had in fact been assassinated, and this belief remains widely held. One western correspondent in Ethiopia at the time commented, "While it is not known what actually happened, there are strong indications that no efforts were made to save him. It is unlikely that he was actually killed. Such rumors were bound to arise no matter what happened, given the atmosphere of suspicion and distrust prevailing in Addis Ababa at the time."

The Soviet-backed Derg fell in 1991. In 1992, the Emperor's bones were found under a concrete slab on the palace grounds; some reports suggest that his remains were discovered beneath a latrine. For almost a decade thereafter, as Ethiopian courts attempted to sort out the circumstances of his death, his coffin rested in Bhata Church, near his great uncle Menelik II's imperial resting place. On 5 November 2000, Haile Selassie was given an Imperial funeral by the Ethiopian Orthodox church. The post-communist government refused calls to declare the ceremony an official imperial funeral. Although such prominent Rastafarian figures as Rita Marley and others participated in the grand funeral, most Rastafari rejected the event and refused to accept that the bones were the remains of Haile Selassie. There remains some debate within the Rastafari movement as to whether Haile Selassie actually died in 1975.