The Ajuran Sultanate, natively referred to as Ajuuraan, and often simply Ajuran, was a medieval Muslim Empire in the Horn of Africa. Founded by Somali Sultans it ruled over large parts of the Horn of Africa during the Middle Ages. It rose to power in the 13th century and would dominate the Indian Ocean trade for centuries to come. Through a strong centralised administration and an aggressive military stance towards invaders, the Ajuran Empire successfully resisted Oromo invasions from the west and fought against Portuguese incursions from the east.

The Oromo expansions, also known as the Oromo migrations or the Oromo invasions, were a series of expansions in the 16th and 17th centuries by the Oromo. Prior to their great expansion in the 16th century, the Oromo inhabited only the area of what is now modern-day southern Ethiopia and northern Kenya. Over the centuries due to many factors, mostly the wars between Adal Sultanate and Ethiopia would further encourage the numerous Oromo tribes to expand towards central and eastern modern Ethiopia.