Horn of Africa polity was succeeded by the Sultanate of Ifat around 1285. Ifat was governed from its capital at Zeila in northern Somalia and was the easternmost district of the former Shewa Sultanate. The Adal Sultanate was a medieval multi-ethnic Muslim state centered in the Horn region. At its height, it controlled large parts of Somalia, Ethiopia, Djibouti and Eritrea. Many of the historic cities in the region, such as Amud, Maduna, Abasa, Berbera, Zeila and Harar, flourished during the kingdom's golden age. This period that left behind numerous courtyard houses, mosques, shrines and walled enclosures. Under the leadership of rulers such
German horn excessive. Although the French firm Jérôme Thibouville-Lamy in about 1928 introduced a piston-valved double-horn with ascending third valve, designed in collaboration with the horn player Louis Vuillermoz, the double horn has continued to be identified mainly as a German horn. The double horn essentially combines two instruments into a single frame: one horn in F, and a second, higher horn keyed in B. Like the single horn it has three valves, but each has a double set of tubing, the first tuned in F and a shorter set in B. By depressing a fourth valve (usually operated by the thumb),