The kingdom of Aksum conquered Kush in Eastern Africa in A. D. 350. Aksum took over many of Kush's trade routes, including the chief city Adula, where such goods as ivory and gold were traded with Egypt, India, Arabia, and the Roman Empire. Aksum converted to Christianity in A. D. 300, making today's Ethiopia one of the oldest Christian areas of the world. King Ezana ruled Aksum during its peak years. He expanded the kingdom by conquering part of the Arabian peninsula. Aksum was eventually invaded by Arabic peoples, and was no longer by 900.

Aksum became known for its stone architecture. Some tall stelae, or pillars, still stand. This area was also the first sub-Saharan kingdom to develop its own writing system and to mint its own coins. The area that is today Ethiopia had a wealth of gold from which coins were made by Aksumites and Romans. People would travel by sea and land to the gold region to trade their goods, such as meat, salt, and iron for pea-sized nuggets of locally-mined gold. Around A. D. 700, the Baghdad caliphate took control of the shipping on the Red Sea and Aksum lost its importance. The ruler of Aksum was overthrown by a group of local nobles called the Zagwe. Their ruler, Lalibela, ruled Ethiopia from about 1185 to 1225.