The sultanate of Zeila became a powerful Adal Empire by thirteenth century from Gulf of Aden to the present Ethiopian city of Harar. Its outstanding ruler, Imam Ahmad ibn Ibrahim al-Ghazi (1506-1543), had succeeded in conquering a considerable portion of Ethiopia and penetrated to North reaching Kassala in 1535. Ethiopians were completely broken and the defeated King appealed to Potugal for assistance. Joint forces of Portugal and Ethiopia attacked Imam Ahmad and inflicted defeat. On the death of Imam Ahmad in 1543 the Adal Empire disintegrated.

British penetration began in 1839 and by treaty made it their protectorate. The Italians got interested in the area also and by a treaty with the Sultan of Zanzibar acquired control over Mogadishu and other coastal towns facing the Indian Ocean. Syed Mohammad ibn Abdullah Hassan, a somali religious leader, started a struggle for independence from colonial rule and fought the British and the Italians for 21 years, till he was finally defeated in 1920. But the nationalist feeling of the Somalis was not suppressed. British-Italian conflict to possess the territory started in 1936 and finally British emerged victor in May, 1941. In 1950 the former Italian Somaliland minus Ogaden was placed under UN Trust while British Somaliland continued as before. However, the British gave independence to British Somaliland on 26th June, 1960 to enable it to unite with the UN Somalia. On 1st July, 1960 the Republic of Somalia was proclaimed.