The Somaliland campaign, also called the Anglo-Somali War or the Dervish War, was a series of military expeditions that took place between 1900 and 1920 in modern-day Somalia. The British were assisted in their offensives by the Ethiopians and Italians. During the First World War (1914–1918), the Dervish leader Mohammed Abdullah Hassan received support for a time, from the Emperor Iyasu V of Ethiopia, he was also sent a letter of support by the Ottomans though it was intercepted by Italian agents in Aden and may never have reached him. The conflict ended when the British aerially bombed the Dervish capital of Taleh in February 1920. British Somaliland Although nominally part of the Ottoman Empire, Yemen and the sahil (including Zeila) came progressively under the control of Muhammad Ali, ruler of Egypt, between 1821 and 1841. After the Egyptians withdrew from the Yemeni seaboard in 1841, Haj Ali Shermerki, a successful and ambitious Somali merchant, purchased from them executive rights over Zeila. Shermerki's governorship had an instant effect on the city, as he manoeuvred to monopolize as much of the regional trade as possible, with his sights set as far as Harar and the Ogaden. Shermerki was later succeeded as Governor of Zeila by Abu Bakr Pasha, a local Afar statesman. In 1874–75, the Egyptians obtained a firman from the Ottomans by which they secured claims over the city. At the same time, the Egyptians received British recognition of their nominal jurisdiction as far east as Cape Guardafui. In practice, however, Egypt had little authority over the interior and their period of rule on the coast was brief, lasting only a few years (1870–84). The British Somaliland protectorate was subsequently established in the late 1880s after the ruling Somali authorities signed a series of protection treaties granting the British access to their territories on the northwestern coast. Among the Somali signatories were the Gadabuursi (1884), Habar Awal (1884 and 1886), and Warsangali.