South West Africa (SWA) or Namibia has been administered by South Africa since South African forces occupied the territory in 1915 at the request of the Allied Powers in World War I. Prior to the invasion, SWA had been under German rule for more than three decades. The German presence dated from 1883 when Heinrich Vogelsang, acting on behalf of the merchant Lüderitz, bought some land bordering on the historic bay of Angra Pequena from the Oorlams Nama at Bethanien. It was later renamed Lüderitzbucht. This was followed by the declaration of a German protectorate over the interior in 1884. German SWA, however, did not include Walvis Bay and the Penguin Islands which had been annexed by Britain for the period 1861 to 1878 and incorporated into the Cape Colony in 1884. German settlers established towns and introduced commercial farming in SWA. Diamonds were discovered along the southern Namib coast in 1908 and railways built to transport the copper and lead deposits mined at Tsumeb. Christian missions had been active in the territory since the early 19th century, notably the London, Rhenish and Finnish missionary societies. They were followed by others, including those of the Catholic and Dutch Reformed churches. Today at least 90 per cent of the 1,2 million inhabitants belong to Christian churches, of which the Evangelical Lutheran Church (Elcin) is the largest.