On 27 February 1885, Kaiser Wilhelm I signed a Schutzbrief, or Imperial Charter, drafted under Bismarck's supervision at the Foreign Ministry, which placed about 60,000 square miles of east African territory under the protection of the German Reich. Incorporating the interior districts directly west of the island of Zanzibar, the German protectorate was based on treaties made with local chieftains late the previous autumn by Carl Peters, founder and co-director of the Gesellschaft für deutsche Kolonisation. Bismarck, in endorsing Peters' claims to territory in east Africa, approved as well the sending out of further expeditions. The eastern boundaries of the soon to be established Congo Free State were described as the anticipated limit of continued annexations which the German company was authorized to undertake at once.