| Ethiopian Empire
| Adal Sultanate
|Commanders and leaders|
|Dawit II of Ethiopia †
Gelawdewos of Ethiopia †
Cristóvão da Gama †
Bahr negus Yeshaq
|Ahmad ibn Ibrihim al-Ghazi †
Nur ibn Mujahid
Islam was introduced to the Horn of Africa early on from the Arabian peninsula, shortly after the hijra. In the late 800s, Al-Yaqubi wrote that Muslims were living along the northern Somali seaboard. He also mentioned that the Adal kingdom had its capital in the city, suggesting that the Adal Sultanate with Zeila as its headquarters dates back to at least the 9th or 10th centuries. According to I.M. Lewis, the polity was governed by local dynasties consisting of Somalized Arabs or Arabized Somalis, who also ruled over the similarly-established Sultanate of Mogadishu in the Benadir region to the south. Adal's history from this founding period forth would be characterized by a succession of battles with neighbouring Abyssinia.
Between 1529 and 1559, the Somali military leader Imam Ahmad ibn Ibrihim al-Ghazi defeated several Ethiopian emperors and embarked on a conquest referred to as the Futuh Al-Habash ("Conquest of Abyssinia"), which brought three-quarters of Christian Abyssinia under the power of the Muslim Sultanate of Adal. With an army mainly composed of Somalis, Al-Ghazi's forces and their Ottoman allies came close to extinguishing the ancient Ethiopian kingdom. However, the Abyssinians managed to secure the assistance of Cristóvão da Gama's Portuguese troops and maintain their domain's autonomy. Both polities in the process exhausted their resources and manpower, which resulted in the contraction of both powers and changed regional dynamics for centuries to come. Many historians trace the origins of hostility between Somalia and Ethiopia to this war. Some scholars also argue that this conflict proved, through their use on both sides, the value of firearms such as the matchlock musket, cannons and the arquebus over traditional weapons.
Course of the war 
In 1529, Imam Ahmad's Adal troops defeated a larger Ethiopian contingent at the Battle of Shimbra Kure. The victory came at a heavy cost but it solidified the Somali forces' morale, providing proof that they could stand up to the sizable Ethiopian army.
The victories that gave the followers of Imam Ahmad the upper hand came in 1531. The first was at Antukyah, where cannon fire at the start of the battle panicked the Ethiopian soldiers. The second was on 28 October at Amba Sel, when troops under the Imam not only defeated but dispersed the Ethiopian army and captured items of the Imperial regalia. These victories allowed the Somalis to enter the Ethiopian highlands, where they began to sack and burn numerous churches, including Atronsa Maryam, where the remains of several Emperors had been interred. The country was looted by the Ahmad's forces, who destroyed several Christian monuments and oppressed the non-Muslim Amhara and Tigray.
Dawit II died in 1540 and his heir was captured by the forces of Imam Ahmad; the Empress was unable to react as she was besieged in the capital. In 1543, Ethiopian guerrillas were able to defeat the Somalis with the help of the Portuguese navy, which brought 400 musketeers led by Cristóvão da Gama. Although da Gama was captured in the Battle of Wofla, and later killed, in 1543 Ahmad himself was killed in the Battle of Wayna Daga, with the help of surviving Portuguese musketeers. The death of Imam Ahmad and the victory in the Battle of Wayna Daga caused the semi-collapse of Ahmad's army and forced a Somali retreat from Ethiopia.
Mohammed Hassan has plausibly argued that because the participants in this conflict weakened each other severely, this provided an opportunity for the Oromo people to migrate into the lands south of the Abay east to Harar and make them their homelands.
See also 
- Henze, Paul B. (2000). Layers of Time: A History of Ethiopia. Hurst & Company. p. 89. ISBN 1850655227.
- Historical dictionary of Ethiopia By David Hamilton Shinn, Thomas P. Ofcansky, Chris Prouty pg 171
- Encyclopedia Americana, Volume 25. Americana Corporation. 1965. p. 255.
- Lewis, I.M. (1955). Peoples of the Horn of Africa: Somali, Afar and Saho. International African Institute. p. 140.
- Saheed A. Adejumobi, The History of Ethiopia, (Greenwood Press: 2006), p.178
- Encyclopaedia Britannica, inc, Encyclopedia Britannica, Volume 1, (Encyclopaedia Britannica: 2005), p.163
- John L. Esposito, editor, The Oxford History of Islam, (Oxford University Press: 2000), p. 501
- David D. Laitin and Said S. Samatar, Somalia: Nation in Search of a State (Boulder: Westview Press, 1987).
- Cambridge illustrated atlas, warfare: Renaissance to revolution, 1492-1792 By Jeremy Black pg 9
- "Local History in Ethiopia" (pdf) The Nordic Africa Institute website (accessed 28 January 2008)
- Mohammed Hassen, The Oromo of Ethiopia: A History (1570-1860) Trenton: Red Sea Press, 1994.