The Heligoland–Zanzibar Treaty (; also known as the Anglo-German Agreement of 1890) was an agreement signed on 1 July 1890 between the German Empire and the United Kingdom. The accord gave Germany control of the Caprivi Strip (a ribbon of land that gave German South-West Africa access to the Zambezi River), the strategically located island of Heligoland in the North Sea, and the heartland of German East Africa. In return, Germany recognized British authority in Zanzibar. Heligoland was needed to control the new Kiel Canal and the approaches to Germany's North Sea ports. Britain used Zanzibar as a key link in the British control of East Africa. Terms Germany gained the islands of Heligoland () in the North Sea, originally possession of the dukes of Holstein-Gottorp but since 1814 a British possession, the so-called Caprivi Strip in what is now Namibia, and a free hand to control and acquire the coast of Dar es Salaam that would form the core of German East Africa (later Tanganyika, now the mainland component of Tanzania). In exchange, Germany handed over to Britain the protectorate over the small sultanate of Wituland (, on the Kenyan coast) and parts of East Africa vital for the British to build a railway to Lake Victoria, and pledged not to interfere with British actions vis-à-vis the independent Sultanate of Zanzibar (i.e. the islands of Unguja and Pemba). In addition, the treaty established the German sphere of interest in German South West Africa (most of present-day Namibia) and settled the borders between German Togoland and the British Gold Coast (now Ghana), as well as between German Kamerun and British Nigeria. Consequences Britain divested itself of a naval base which covered the approaches to the main German naval bases in the North Sea, but which would be impossible to defend as Germany built up its navy. It immediately declared a protectorate over Zanzibar and, in the subsequent 1896 Anglo-Zanzibar War, gained full control of the sultanate. The treaty served German chancellor Leo von Caprivi's aims for settlement with the British. After the 1884 Berlin Conference, Germany had lost in this phase of the "Scramble for Africa": the German East Africa Company under Carl Peters had acquired a strip of land on the Tanganyikan coast (leading to the 1888 Abushiri Revolt), but had never had any control over the islands of the Zanzibar sultanate; the Germans gave away no vital interest.