Oromo clans had moved into southern Ethiopia from about 1550. These nomadic people had no central government but lived by raiding the more settled states along the Nile. Both the Islamic states in the Sudan and the Christian kingdom of Abyssinia were plagued by these warlike people. By the reign of Emperor Iyasu II of Gondar-Abyssinia (he ruled 1730-1755), many of the Oromo had been recruited into the royal army. Thus, their warlike energies were used by Iyasu to strengthen the imperial Gondar dynasty, both against the traditional Abyssinian nobles as well as against foreign enemies. Eventually, Oromo (related to Kushite) became the common language at the royal court. Most Abyssinisans spoke Amhara, a Semitic language related to Arabic.

The rule of the kings of Gondar is ended by 1769. In Ethiopian history, the period of 1769 to 1855 is called the "Era of the Princes". Ras Mikael Sehul, a noble (ras is a title more or less meaning "marshal"--in Amhara it literally means "head"), became effective ruler after the death of Iyasu in 1755. While kings continued to rule as figureheads, Mikael is the real power, removing kings as he wished. He even had two kings killed at his order. But after Mikael's death, the country fell apart as no single ras is strong enough to take his place. Each province became a virtual kingdom of its own, and constant warfare existed between the various provinces. At one time, around 1800, there were six rival emperors, each claiming rule over the whole of Abyssinia.

The Scotsman James Bruce lived and worked in Ethiopia between 1769 and 1772 while travelling along the Nile River to find its source. His experiences were published in five volumes titled "Travels to Discover the Source of the Nile".

After consolidating their base on the East African coast by the mid-1500s, the Portuguese attempt to expand inland. The Mwene Mutapa Empire is conquered, but the city of Great Zimbabwe, capital of the breakaway Changmire Kingdom is not reached. Dombo Urozwi, king of Changmire, successfully resists Portuguese expansion and finally drives them out of Zimbabwe.

Arabs from the Sultanate of Oman also contest the Portuguese expansion. The Arabs had old historic trade and cultural links with the Swahili city states. In 1631 Mombasa revolts against the Portuguese, but the revolt is defeated. In 1698, the Omanis attack and defeat the Portuguese, driving them out of the Swahili cities of

Mombasa, Zanzibar, Pemba and Kilwa. The Portuguese hold out south of the Ruvuma River, what becomes their colony of Mozambique.