Whether by or against the wish of the home government, the limits of British authority continued to extend. The Basotho, who dwelt in the upper valleys of the Orange River, had subsisted under a semi-protectorate of the British government from 1843 to 1854; but having been left to their own resources on the abandonment of the Orange sovereignty, they fell into a long exhaustive warfare with the Boers of the Orange Free State. On the urgent petition of their chief Moshesh, they were proclaimed British subjects in 1868, and their territory became part of the Cape Colony in 1871 (see Basutoland). In the same year, the southeastern part of Bechuanaland was annexed to Britain under the title of Griqualand West. This annexation was a consequence of the discovery there of rich diamond mines, an event which was destined to have far-reaching results.