Somaliland campaign

The Somaliland campaign, also called the Anglo-Somali War or the Dervish rebellion, was a rebellion in the Horn of Africa, by the Dervish, a Somali movement led by Sayid Muhammed Abdullah Hassan, which continued independently for 21 years between 1899 and 1920.

The opening battle of the rebellion saw the Dervish attack the Ethiopian garrison at Jigjiga in March 1900 and take control of parts of the eastern Ogaden region. The Dervish then declared war on the British colonial administration in Somaliland. They would also attack and seize parts of Italian Somaliland. The British launched five military expeditions, mainly in the Nugaal Valley, between 1900 and 1920 against the Dervish. They were assisted in their offensives by the Ethiopian Empire and the Kingdom of Italy. The British also armed rival Somali clans against the Dervish. The Dervish movement successfully repulsed the British Empire in the first four expeditions, forcing them to retreat to the coastal region and continually raided British controlled parts of Somaliland. The conflict ravaged the region's economy. It has been estimated that around one-third of the population of Somaliland died during the Dervish rebellion.

With the defeat of the Ottoman and German empires in World War I, the Dervish movement lacked any allies. The British thus turned their attention to the Dervishes, and launched a massive combined arms offensive on the Dervish forts. The Dervish retreated to their capital at Taleh, which was aerially bombed and then captured by the British, leading to the fall of the Dervish movement and bringing the conflict to an end.