For centuries, African peoples and empires had been involved in trade and diplomatic relations with those Europeans. The Portuguese were the first Europeans to establish a physical presence in Africa, in the 1480s, but through the 1870s European outposts were restricted to ports along the African coasts focusing on trade and diplomacy. In the second half of the nineteenth century, however, the balance of power began to shift in Europe's favor, and gradually most European nations laid claim to territories on the African Continent.
The most profound changes occurred between 1880-1895. In 1884-85, the Berlin Conference was called to establish the ground rules amongst Europeans claiming territory on the African continent. No African sovereigns or representitives were invited to attend. As the maps illustrate, there was a sudden explosion of European imperial claims on the continent after the conference of Berlin.
The boundaries drawn by Europeans in the late 19th cnetury remain, to a large extent, the boundaries of Africa's independent nations today. When the Organization of African Unity (OAU) first convened in May of 1961, it was decided to leave the current national boarders as they were in order to avoid unnecessary turmoil. Most of the continents 53 sovereign nations gained their independence in the 1960s, while others struggled through the 1970s, the 1980s and even into the 1990s before gaining national independence. The Western Sahara is a region that as late as 2007 had not yet received international recognition as an independent, self-governing, nation-state.