Horn of Africa displays the greatest diversity, a sign often viewed to represent a geographic origin. The Horn of Africa is also the place where the haplogroup E1b1b originated from, Christopher Ehret and Shomarka Keita have suggested that the geography of the E1b1b lineage coincides with the distribution of the Afroasiatic languages. Genetic analysis done on the Afroasiatic speaking population further found that a pre-agricultural back-to-Africa migration into the Horn of Africa occurred through Egypt 23,000 years ago and it brought a non-African ancestry dubbed Ethio-Somali in the region. Together with northern Somalia, Djibouti, the Red Sea coast of Sudan and Eritrea is
Horn of Africa eventually transformed into Islamic Mogadishu, Berbera, Zeila, Barawa and Merka, which were part of the "Berber civilization". The city of Mogadishu came to be known as the "City of Islam" and controlled the East African gold trade for several centuries. During the Middle Ages, several powerful empires dominated the regional trade in the Horn, including the Adal Sultanate, the Ajuran Sultanate, the Warsangali Sultanate, the Zagwe dynasty, and the Sultanate of the Geledi. The Sultanate of Showa, established in 896, was one of the oldest local Islamic states. It was centered in the former Shewa province in central Ethiopia. The