Portuguese overseas expansion began in the fifteenth century, thanks to several factors that gave the small coastal nation an advantage over its larger European neighbors. First, in the 1300s, Portuguese shipbuilders invented several new techniques that made sailing in the stormy Atlantic Ocean more practical. They combined elements of different different types of ships to construct stronger, roomier and more maneuverable caravels. They also took advantage of more reliable compasses for navigation, and benefitted from the school for navigation created by Prince Henry "the Navigator" (1394-1460) at Sagres in 1419. Starting with voyages to Madeira and the Azores (islands in the Atlantic) in the first part of the 14th century, the Portuguese systematically extended their explorations as far as Japan by the 16th century. In the process, they established forts and settlements along the West and East African coasts. In the 16th through 18th centuries, the Portuguese lost their lead to other European nations, notably England and France, but played a major role in the slave trade to satisfy the demand for labor in Brazil.

By the beginning of the 19th century, Portugal controlled outposts at six locations in Africa. One was the Cape Verde Islands, located about 700 miles due west of Dakar, Senegal. Discovered by Alvise da Cadamosta of Venice in 1456 and claimed for Portugal by Diogo Gomes about 1458, this archipelago of eight major islands was devoted to sugar cultivation using slaves taken from the African mainland. The Portuguese once had extensive claims on the West African coast -- since they were the first Europeans to explore it systematically -- but by 1800 they were left with only a few ports at the mouth of the Rio Geba in what is now known as the Guinea-Bisseau. To the east, the Portuguese controlled the islands of Sao Tomé & Principe, located south of the mouth of the Niger River. Like the Cape Verde Islands, they were converted to sugar production in the early 16th century using slaves acquired on the mainland in the vicinity of the Congo River. By the end of the 19th century, Portuguese landowners had successfully introduced cocoa production using forced African labor. (That story was the subject of Chocolate on Trial by Lowell J. Satre.)

Further south, the Portuguese claimed both sides of the mouth of the Congo River, as well as the Atlantic coast as far south as the Rio Cunene. In practical terms, they only controlled a few port cities including Cabinda (north of the Congo River mouth), Ambriz (south of the Congo's mouth), Luanda and Benguela (on the Angolan coast) plus some river towns in the Angolan interior.

Despite these holdings, the Portuguese hold in Africa was extremely weak. The first cause was the small size of Portugal's population, coupled with the lack of popular support for overseas empire. Exploration and conquest began as an enterprise supported by the nobility, and Portuguese peasants rarely participated unless forced to do so. When the common people of Portugal did chose to emigrate, they were much more likely to head to Brazil than to Africa. To induce Europeans to move to its African holdings, the Portuguese government resorted to releasing degradados - convicted criminals -- from prison in exchange for accepting what amounted to exile in Africa. Angola, in particular, gained a reputation as a Portuguese penal colony. Also, since the European population remained almost entirely male, the Portuguese birth rate was negligible, although plenty of "Afro-Lusitanians" were born to African mothers. As a result, the European population of Portugal's African settlements was never large, and community leaders were just as likely to owe their loyalty to local African governments as they did to the distant Portuguese government.

As it did everywhere else, the industrial revolution stimulated change in Portuguese Africa. It created a demand for tropical raw materials like vegetable oils, cotton, cocoa and rubber, and it also created a need for markets to purchase the expanded quantity of goods issuing from factories. In Portugal's case, most of the factories were located in England, which had had a special relationship with Portugal ever since Philippa, the daughter of England's John of Gaunt, married John of Avis, the founder of the Portuguese royal family. Prodded by Napoleon's invasion and English support for the royal family's escape to Brazil, King Joao and his successors eliminated tariffs, ended trade monopolies and generally opened the way for British merchants to become dominant in the Portuguese empire. At times, that caused friction, such as when both British and Portuguese explorers claimed the Shire Highlands (located in modern Malawi), but for the most part Great Britain supported the Portuguese position in exchange for incorporating Portugal's holdings into the British economic sphere.

Unfortunately, with neither a large European population nor African wage earners, the Portuguese colonies offered poor markets for manufactured goods from the private sector. Consequently, industrialization arrived in the form of government programs designed to improve internal communications and increase the number of European settlers. During the late 1830s, the government headed by Marquis Sá da Bandeira tried to encourage Portuguese farmers to emigrate to Angola, with little success. Between 1845 and 1900, the European population of Angola rose from 1,832 to only about 9,000. European immigration to Mozambique showed slightly better results -- about 11,000 in 1911 -- but many were British from South Africa rather than Portuguese.

The other major force for change was the rivalries that developed between European nations in the century between the end of the Napoleonic Wars and the outbreak of World War I. Forbidden from fighting each other by the "balance of power" established by the Treaty of Vienna, they competed in other ways including scientific discoveries, athletic competitions, exploration and proxy wars. Although not a major power, Portugal participated in the competition, especially by sending out explorers to solidify their claim to all of the land between Angola and Mozambique. That bought them into conflict with men like Cecil Rhodes, whose own vision of an empire from "Cape to Cairo" required that the British gain control over the same land. European rivalries appeared most often as commercial competition, and in 19th century Africa, that included the right to move goods by steamboat along rivers. The British had a head start thanks to their early adoption of steam technology and their supremacy on the high seas. They became the strongest proponents of the principle of "free trade" which prohibited countries from creating legal barriers to another country's merchants. Occasionally, Portuguese leaders resisted, but the British alliance provided sufficient benefits to convince various administrations to go along (although they faced revolts at home and in their colonies). It was Portugal's claim to the land on either side of the mouth of the Congo River that triggered the events leading up to the Congress of Berlin. That claim, which dated from Diogo Cao's voyage in 1484, gave Portugal places from which naval patrols could control access to Africa's largest river system. The British eyed this arrangement with suspicion for years, but paid tariffs (like everyone else) for the right to trade there, mostly for slaves.

Portuguese claims in Southern Africa 1877-1879 -- Alexandre de Serpa Pinto became the first Portuguese to cross southern Africa from Benguela to Durban. 1884-1885 -- HermenegiIdo de Brito Capelo and Roberto Ivens crossed from Mo‡amedes in southern Angola to Quellimane in northern Mozambique. 1887 -- Based on the Capelo-Ivens expedition, plus an agreement with the German government, (which also wanted to limit British claims in southern Africa), the Portuguese government produced a map (known as the "rose-colored map) which showed continuous Portuguese land holdings between Angola and Mozambique. 1890 -- The British government issued an ultimatum to the Portuguese government, ordering them to withdraw from the disputed territory. The Portuguese yielded, sparking a domestic outcry that forced King Carlos to name a new cabinet. 1891 -- The British and Portuguese governments signed a treaty that enlarged both Mozambique and Angola, but also recognized Cecil Rhodes' claim to the mineral-rich area that became the future country of Zimbabwe.

After the abolition of slavery got underway, the Portuguese dragged their heels, so in 1839 the British government declared its right to inspect Portuguese ships for evidence of slave trading with or without Portuguese consent. That stirred the Portuguese to action, and in a subsequent series of agreements made in the 1840s, the British acquired the right to land their ships where no Portuguese authorities were present. When the Portuguese refused to renew the agreement in 1853, the British ceased paying tariffs at the ports on either side of the Congo River mouth, claiming that Portugal's claim had expired because they had left the area unoccupied for too long. Portugal reoccupied the ports of Cabinda and Ambriz in 1855, and relations with Great Britain improved after that. The dispute set a precedent, however, that effective occupation was a prerequisite for recognition of colonial claims. The question continued to reappear until 1885 when it was enshrined in the agreements that emanated from the Congress of Berlin.

The Portuguese were the first Europeans to claim territory in sub-Saharan Africa, and their example inspired imitation from other European powers. For the British, the Portuguese were acceptable proxies in the competition with France, Russia and Germany for world domination. For Portuguese governments, the British alliance gave them influence that they could not command themselves, while the idea of a Portuguese empire offered something with which to distract domestic opponents from the struggles initiated by the Napoleonic Wars.

The issues that were raised by Portugal's claims in Africa and the efforts of other countries to whittle them down became the fundamental issues of the Congress of Berlin. In the end, the Congress settled more than the future of Portugal's African holdings -- it also set the rules for any European government which wished to establish an empire in Africa.