Angola's often violent and bloody history is a tale of a potentially rich country well endowed with natural resources that ended up, at the start of the 21st century, as one of the poorest nations on earth.

It's a complex and controversial story that spans 500 years of tribal rivalry, colonialism, slavery, war, independence, proxy war, outside interference, and finally the establishment of a delicate, but – to date – lasting, peace.

The Portuguese Era

In 1483, the Portuguese navigator Diogo Cão first dropped anchor off the shores of northern Angola and unwittingly pre-empted the start of a conflict that, save for a few intermittent lulls, continued for over half a millennium. The land now known as Angola was, at the time, inhabited by a number of small tribes living in loosely defined kingdoms.

Since the 1390s, the northern third of what is now Angola had been part of the Kingdom of the Kongo, a vast tract of land roughly the size of Greece that made contact with Cão's Portuguese emissaries in the 1480s and quickly adopted their own Africanised version of Catholicism. The Kongo were the region's most powerful and influential ethnic group and, using their militaristic clout, they engaged in a series of sporadic wars and skirmishes with other tribes from whom they extracted tribute, most notably the Ambundu.

Faced with an inevitable conflict against the Portuguese who had established a trading port in Luanda in 1576, the Kongo cleverly exploited European colonial rivalries and allied themselves with the Dutch in the 1620s. This unlikely alliance succeeded in briefly expelling the Portuguese from Angola. In 1641 a Dutch fleet under the command of Cornelis Jol invaded and took Luanda while Kongo warriors distracted the Portuguese further inland around the Bengo River. For a brief seven years, Angola was a Dutch colony until the Portuguese won it back in 1648.

Despite their early forays up and down the African coast, the Portuguese had no real desire to settle permanently on the malaria-ridden shores of southern Africa. The more fertile and less threatening lands of Brazil held a far greater attraction for colonial farmers and businessmen. For the next 200 years Portugal's African colonies had only two real functions: a strategic base on the route around the Cape of Good Hope, and a collecting centre for one of the largest forced human migrations in history – namely, slavery.

The exact number of African slaves trafficked from Angola to the Americas will never be known, but it probably numbered in the millions (figures of around 10,000 a year were touted as early as the 1620s). The trade was theoretically abolished in Portugal's colonies in 1836, although a system of forced labour continued in Angola until well into the 20th century.

The Portuguese colonisation of Angola's uncharted interior didn't begin until Africa was rudely carved up by the European powers at the 1885 Berlin Conference. A railway was built from Benguela to the Zambia border in the early 1900s, paving the way for a big push for influence and resources that began after the right-wing Salazar regime grabbed power in Portugal in 1926.

Salazar reintroduced forced labour and implanted white Portuguese settlers in Angola to manage the best land and exploit indentured Africans by working them forcibly on the coffee, maize and sugar plantations.

The Road to Independence

Not surprisingly, slavery did little to endear the colonials to the Angolan people. Clashes first began after WWII and were inflamed in 1961 when colonial authorities began to crush increasingly zealous uprisings by dissidents.

The initial independence movement was split into three main groups that reflected the various tribal affiliations (and international interests) at play in Angola. The National Front for the Liberation of Angola (FNLA) was supported by northern tribes, the Democratic Republic of Congo (DRC) and anti-communist Western countries. The Popular Movement for the Liberation of Angola (MPLA) began with Marxist sensibilities and was supported by southern tribes, the USSR, Cuba and other Soviet allies. The National Union for Total Independence of Angola (Unita) originally had the support of the Ovimbundu people, but later formed alliances with the Portuguese right wing, the USA and apartheid South Africa.

In 1975 the Portuguese finally granted independence to Angola, following the overthrow of the fascist Salazar government at home. But the colonial withdrawal – a mad scramble involving one of the biggest airlifts in history – was legendary for its ineptitude. Overnight, Luanda's commercial heart was converted into a ghost town and the country lost practically all of its qualified human resources and administrative structure. Problems beckoned.

The Civil War & Its Aftermath

Angola in 1975 possessed all the essential ingredients for civil war: a weak, uneven infrastructure, low levels of health and education, two feuding sets of tribal elites, and a large slice of unused government oil revenue seemingly up for grabs. As the Moscow-backed MPLA party stepped into the power vacuum left by the Portuguese, other outside influences thickened the plot further: US communist paranoia, Cuba's ambiguous desire for 'world revolution', South African security obsessions and the woefully inadequate process of decolonisation. The stage was set.

Angola's civil war was a long, protracted affair dominated by foreign intervention. For the next 15 years the hopes and dreams of the Angolan people were thrown aside as foreign governments and Western business interests fought among themselves over a damaged and increasingly beleaguered country.

In 1991, prompted by the end of the Cold War, a ceasefire agreement was set in place by Cuba, the USA and Angola. But the accord broke down the following year after Unita, having lost a general election deemed free and fair by the UN, returned to war with a new-found ferocity, claiming the poll had been rigged. Almost 200,000 people died between May and October 1993 as Unita took war to the provincial cities, destroying most of the road, rail and communications network in the process.

A revamped 'Lusaka Accord' signed in 1994 was consistently violated by both the governing MPLA and Unita, as the discovery of new diamond areas and oilfields allowed both sides to re-arm. Ultimately, UN sanctions against Unita diamonds caused Unita's cash supply to shrivel, and its control of the countryside gradually crumbled. Increasing military defeats drove a desperate Unita deeper into the hinterland and its leader Jonas Savimbi – hunted and on the run – was finally killed in a government operation on 22 February 2002.

A new peace accord was signed on 4 April 2002 and – so far – it has held, 15 years and counting.