Colonial Era: Until the late nineteenth century, the high plateau of present-day Eritrea was a part of the Ethiopian province of Tigray. Its inhabitants, racially, culturally, and linguistically Tigrayan, were subjects of the Ethiopian crown, whereas the surrounding lowlanders were for the most part independent. The boundaries of modern Eritrea were established during the period of Italian colonization that began in the late 1800s. An Italian shipping company, Rubatinno Shipping, purchased the port of Assab from a local ruler. In turn, the Italian government took over the port in 1882, hoping to use Eritrea as a launching point for the colonization of Ethiopia. The Italian presence in the Horn of Africa was formalized in 1889 with the signing of the Treaty of Wuchale with Emperor Menelik II of Ethiopia (r. 1889–1913), although Menelik would later renounce the agreement. For the next half-century, relations between Ethiopia and Italy, despite intermittent diplomatic agreements, were strained by repeated Italian efforts to expand their colonial base into Somali territory and Ethiopia, most notably in 1896, when Ethiopia defeated the Italian army in Tigray. Italian administration of Eritrea brought improvements in the medical and agricultural sectors of Eritrean society. Furthermore, the Italians employed many Eritreans in public service (in particular in the police and public works departments) and oversaw the provision of urban amenities in Asmara and Massawa. In a region marked by cultural, linguistic, and religious diversity, a succession of Italian governors maintained a notable degree of unity and public order.

Benito Mussolini’s rise to power in Italy in 1922 brought profound changes to the colonial government in Eritrea. The Fascists imposed harsh rule that stressed the political and racial superiority of Italians. Segregation was established, and Eritreans were demoted to menial positions in the public sector. Although Rome continued to implement agricultural reforms, these took place largely on farms owned by Italian colonists. The Fascist dictatorship regarded the colony as a strategic base for future aggrandizement and ruled accordingly. True to form, Italy used Eritrea as a base from which to launch its 1935–36 campaign to colonize Ethiopia.

World War II, British Rule, and Federalization: Although Italian colonization in the late nineteenth and early twentieth centuries gave Eritrea its boundaries, Eritrean separatism as a political goal had its roots in World War II. British forces defeated the Italian army in Eritrea in 1941 at the Battle of Keren and placed the colony under British military administration until Allied forces could determine its fate. Absent agreement among the Allies about the status of Eritrea, British administration continued for the remainder of World War II and into 1950. In the immediate postwar years, the British proposed that Eritrea be divided along religious lines and parceled off to Sudan and Ethiopia. The Soviet Union, anticipating a communist victory in the Italian polls, initially supported returning Eritrea to Italy under trusteeship or as a colony. Arab states, seeing Eritrea and its large Muslim population as an extension of the Arab world, sought the establishment of an independent state.

In the absence of Allied agreement, and in the face of Eritrean demands for self-determination, a United Nations (UN) commission was dispatched to the former colony in February 1950 in the hope of finding a solution. The commission proposed the establishment of some form of association with Ethiopia, and the UN General Assembly adopted that proposal along with a provision terminating British administration of Eritrea no later than September 15, 1952. The British, faced with a deadline for leaving, held elections on March 16, 1952, for a Representative Assembly of 68 members, evenly divided between Christians and Muslims. This body in turn accepted a draft constitution put forward by the UN commissioner on July 10. On September 11, 1952, Emperor Haile Selassie of Ethiopia (r. 1930–74) ratified the constitution. The Representative Assembly subsequently became the Eritrean Assembly.

The details of Eritrea’s association with Ethiopia were established by the UN General Assembly resolution of September 15, 1952. It called for Eritrea and Ethiopia to be linked through a loose federal structure under the sovereignty of the emperor. Eritrea was to have its own administrative and judicial structure, its own flag, and control over its domestic affairs, including police, local administration, and taxation. The federal government, which for all intents and purposes was the existing imperial government, was to control foreign affairs (including commerce), defense, finance, and transportation. As a result of exposure to Italian and especially British methods of governance and political life, Eritreans had developed a distinct sense of cultural identity and superiority vis-à-vis Ethiopians, and a desire for political freedoms alien to Ethiopian political tradition. From the start of the federation, however, Haile Selassie attempted to undercut Eritrea’s independent status, a policy that alienated many Eritreans. The emperor pressured Eritrea’s elected chief executive to resign, made Amharic the official language in place of Arabic and Tigrinya, terminated the use of the Eritrean flag, imposed censorship, and moved many businesses out of Eritrea. Finally, in 1962 Haile Selassie pressured the Eritrean Assembly to abolish the federation and return to the imperial Ethiopian fold, much to the dismay of those in Eritrea who favored a more liberal political order.

The Armed Struggle for Independence: Militant opposition to the incorporation of Eritrea into Ethiopia had begun in 1958 with the founding of the Eritrean Liberation Movement (ELM), an organization made up mainly of students, intellectuals, and urban wage laborers. The ELM engaged in clandestine political activities intended to cultivate resistance to the centralizing policies of the imperial state. By 1962, however, the ELM had been discovered and destroyed by imperial authorities.

Even as the ELM was being neutralized, a new organization of Eritrean nationalists was forming. In 1960 Eritrean exiles in Cairo founded the Eritrean Liberation Front (ELF). In contrast to the ELM, from the outset the ELF was bent on waging armed struggle on behalf of Eritrean independence. The ELF was composed mainly of Eritrean Muslims from the rural lowlands on the western edge of the territory. In 1961 the ELF's political character was vague, but radical Arab states such as Syria and Iraq sympathized with Eritrea as a predominantly Muslim region struggling to escape oppression and imperial domination. These two countries therefore supplied military and financial assistance to the ELF.

The ELF initiated military operations in 1961 and intensified its activities in response to the dissolution of the federation in 1962. By 1967 the ELF had gained considerable support among peasants, particularly in Eritrea's north and west, and around the port city of Massawa. Haile Selassie attempted to calm the growing unrest by visiting Eritrea and assuring its inhabitants that they would be treated as equals under the new arrangements. Although he doled out offices, money, and titles in early 1967 in the hope of co-opting would-be Eritrean opponents, the resistance persisted.

By 1971 ELF activity had become enough of a threat that the emperor had declared martial law in Eritrea and had deployed roughly half his army to contain the struggle. Internal disputes over strategy and tactics, however, eventually led to the ELF's fragmentation and the founding in 1972 of another group, the Eritrean People's Liberation Front (EPLF). The leadership of this multiethnic movement came to be dominated by leftist, Christian dissidents who spoke Tigrinya, Eritrea's predominant language. Sporadic armed conflict ensued between the two groups from 1972 to 1974, even as they fought Ethiopian forces.

In September 1974, a group of Ethiopian military officers deposed the emperor and established a military government in Addis Ababa known as the Derg, which allied itself with the Soviet Union. The Derg immediately turned its attention to the Eritrean question. Some in its ranks pressed for a decisive military solution, while others favored a negotiated settlement. Influential Derg nationalists, like the imperial regime, endorsed the ideal of "Greater Ethiopia," that is, a unitary, multiethnic state, and eventually decided to continue to use force in dealing with Eritrean secessionists. In response, the ELF and EPLF maintained their struggle for Eritrean independence. Armed conflict between the Derg and (mostly) the EPLF continued throughout the 1970s and 1980s, with neither side able to score a decisive victory. In particular, the EPLF stronghold of Nakfa in northern Eritrea withstood repeated assaults by the Ethiopian army. Beginning in March 1988, however, a series of offensives against demoralized Ethiopian forces eventually led to EPLF control of all Eritrea by late May 1991. At the same time that the EPLF was defeating the Ethiopian army in Eritrea, Tigrayan and allied rebel forces took over northern Ethiopia and drove the Derg from power.

Independence: After a referendum showing that nearly 100 percent of Eritreans favored separation, Eritrea gained independence from Ethiopia on May 24, 1993, a development many Ethiopians opposed. Isaias Afwerki, the leader of the EPLF, became the first president of Eritrea. In 1994 the EPLF became a political party, the People’s Front for Democracy and Justice. It remains the only legal political party in Eritrea. President Isaias and his counterpart in Addis Ababa, Meles Zenawi, a fellow Tigrayan, established a cordial relationship, and a variety of agreements were signed between the two nations in the years following independence. Five years after independence, however, tensions over economic policies and border disputes led to war between the two impoverished nations. Before a cease-fire was reached in June 2000, an estimated 100,000 soldiers had lost their lives, and a quarter of the population of Eritrea had been displaced by fighting. In addition, Eritrea suffered extensive damage to its already weak infrastructure and economy, from which it has yet to recover. On December 12, 2000, Eritrea and Ethiopia signed a final peace agreement, but they continue to quarrel over the precise demarcation of their common border.

As of mid-2005, Eritrea’s relations with Ethiopia remain extremely tense. Some 3,300 UN peacekeepers patrol a demilitarized zone inside Eritrea to monitor the cease-fire, and the possibility of renewed warfare cannot be ruled out. Eritrea’s relations with Sudan and the West are problematic, and the nation has become increasingly isolated. Although a constitution has been adopted that calls for elections and political reforms, these have yet to take place. The government of Isaias Afwerki has become intolerant and authoritarian; it has imposed press censorship and has imprisoned many of its political opponents. Discontent is widespread and growing but is harshly suppressed. Today, Eritrea is free from Ethiopian domination, but it is far from a democratic state.