The Portuguese Empire (Portuguese: Império Português), also known as the Portuguese Overseas (Ultramar Português) or the Portuguese Colonial Empire (Império Colonial Português), was composed of the overseas colonies and territories governed by Portugal. One of the longest-lived empires in world history, it existed for almost six centuries, from the capture of Ceuta in 1415, to the handover of Portuguese Macau to China in 1999. The empire began in the 15th century, and from the early 16th century it stretched across the globe, with bases in North and South America, Africa, and various regions of Asia and Oceania. The Portuguese Empire has been described as the first global empire in history, a description also sometimes claimed by the Spanish Empire.
The Portuguese Empire originated at the beginning of the Age of Discovery, and the power and influence of the Kingdom of Portugal would eventually expand across the globe. In the wake of the Reconquista, Portuguese sailors began exploring the coast of Africa and the Atlantic archipelagos in 1418–19, using recent developments in navigation, cartography and maritime technology such as the caravel, with the aim of finding a sea route to the source of the lucrative spice-trade. In 1488 Bartolomeu Dias rounded the Cape of Good Hope, and in 1498 Vasco da Gama reached India. In 1500, either by an accidental landfall or by the crown's secret design, Pedro Álvares Cabral discovered Brazil on the South American coast.
Over the following decades, Portuguese sailors continued to explore the coasts and islands of East Asia, establishing forts and factories as they went. By 1571 a string of naval outposts connected Lisbon to Nagasaki along the coasts of Africa, the Middle East, India and South Asia. This commercial network and the colonial trade had a substantial positive impact on Portuguese economic growth (1500–1800), when it accounted for about a fifth of Portugal's per-capita income.
When King Philip II of Spain (Philip I of Portugal) seized the Portuguese crown in 1580 there began a 60-year union between Spain and Portugal known to subsequent historiography as the Iberian Union. The realms continued to have separate administrations. As the King of Spain was also King of Portugal, Portuguese colonies became the subject of attacks by three rival European powers hostile to Spain: the Dutch Republic, England, and France. With its smaller population, Portugal found itself unable to effectively defend its overstretched network of trading posts, and the empire began a long and gradual decline. Eventually, Brazil became the most valuable colony of the second era of empire (1663–1825), until, as part of the wave of independence movements that swept the Americas during the early 19th century, it broke away in 1822.
The third era of empire covers the final stage of Portuguese colonialism after the independence of Brazil in the 1820s. By then, the colonial possessions had been reduced to forts and plantations along the African coastline (expanded inland during the Scramble for Africa in the late 19th century), Portuguese Timor, and enclaves in India (Portuguese India) and China (Portuguese Macau). The 1890 British Ultimatum led to the contraction of Portuguese ambitions in Africa.
Under António Salazar (in office 1932–1968), the Second Portuguese Republic made some ill-fated attempts to cling on to its last remaining colonies. Under the ideology of Pluricontinentalism, the regime renamed its colonies "overseas provinces" while retaining the system of forced labour, from which only a small indigenous élite was normally exempt. In 1961 India annexed Goa and Dahomey (now Benin) annexed Fort of São João Baptista de Ajudá. The Portuguese Colonial War in Africa lasted from 1961 until the final overthrow of the Estado Novo regime in 1974. The so-called Carnation Revolution of April 1974 in Lisbon led to the hasty decolonization of Portuguese Africa and to the 1975 annexation of Portuguese Timor by Indonesia. Decolonization prompted the exodus of nearly all the Portuguese colonial settlers and of many mixed-race people from the colonies. Portugal returned Macau to China in 1999. The only overseas possessions to remain under Portuguese rule, the Azores and Madeira, both had overwhelmingly Portuguese populations, and Lisbon subsequently changed their constitutional status from "overseas provinces" to "autonomous regions".
The origin of the Kingdom of Portugal lay in the reconquista, the gradual reconquest of the Iberian peninsula from the Moors. After establishing itself as a separate kingdom in 1139, Portugal completed its reconquest of Moorish territory by reaching Algarve in 1249, but its independence continued to be threatened by neighbouring Castile until the signing of the Treaty of Ayllón in 1411.
Free from threats to its existence and unchallenged by the wars fought by other European states, Portuguese attention turned overseas and towards a military expedition to the Muslim lands of North Africa. There were several probable motives for their first attack, on the Marinid Sultanate (in present-day Morocco). It offered the opportunity to continue the Christian crusade against Islam; to the military class, it promised glory on the battlefield and the spoils of war; and finally, it was also a chance to expand Portuguese trade and to address Portugal's economic decline.
In 1415 an attack was made on Ceuta, a strategically located North African Muslim enclave along the Mediterranean Sea, and one of the terminal ports of the trans-Saharan gold and slave trades. The conquest was a military success, and marked one of the first steps in Portuguese expansion beyond the Iberian Peninsula, but it proved costly to defend against the Muslim forces that soon besieged it. The Portuguese were unable to use it as a base for further expansion into the hinterland, and the trans-Saharan caravans merely shifted their routes to bypass Ceuta and/or used alternative Muslim ports.