South West Africa (Afrikaans: Suidwes-Afrika; Dutch: Zuidwest-Afrika; German: Südwestafrika) was the name for modern-day Namibia when it was under South African administration, from 1915 to 1990. South West Africa (Afrikaans: Suidwes-Afrika; Dutch: Zuidwest-Afrika; German: Südwestafrika) was the name for modern-day Namibia when it was under South African administration, from 1915 to 1990. Previously the colony of German South West Africa from 1884, it was made a League of Nations mandate of the British-ruled Union of South Africa following Germany's losses in World War I. Although the mandate was abolished by the UN in 1966, South African rule continued despite it being illegal under international law. The territory was administered directly by the South African government from 1915 to 1978, when the Turnhalle Constitutional Conference laid the groundwork for semi-autonomy. During an interim period between 1978 and 1985, South Africa gradually granted South West Africa a limited form of home rule, culminating in the formation of a Transitional Government of National Unity. In 1990, South West Africa was granted independence as the Republic of Namibia with the exception of Walvis Bay and the Penguin Islands, which continued to remain under South African rule until 1994. As a German colony from 1884, it was known as German South West Africa (Deutsch-Südwestafrika). Germany had a difficult time administering the territory, which experienced many insurrections against the harsh German rule, especially those led by guerilla leader Jacob Morenga. The main port, Walvis Bay, and the Penguin Islands were annexed by the UK in 1878, becoming part of the Cape Colony in 1884. Following the creation of the Union of South Africa in 1910, Walvis Bay became part of the Cape Province. As part of the Heligoland-Zanzibar Treaty in 1890, a corridor of land taken from the northern border of Bechuanaland, extending as far as the Zambezi river, was added to the colony. It was named the Caprivi Strip (Caprivizipfel) after the German Chancellor Leo von Caprivi. In 1915, during South West Africa Campaign of World War I, South Africa captured the German colony. After the war, it was declared a League of Nations Class C Mandate territory under the Treaty of Versailles, with the Union of South Africa responsible for the administration of South West Africa. From 1922, this included Walvis Bay, which, under the South West Africa Affairs Act, was governed as if it were part of the mandated territory. South West Africa remained a League of Nations Mandate until World War II with the collapse of the League of Nations. The Mandate was supposed to become a United Nations Trust Territory when League of Nations Mandates were transferred to the United Nations following World War II. The Prime Minister, Jan Smuts, objected to South West Africa coming under UN control and refused to allow the territory's transition to independence, instead seeking to make it South Africa's fifth province in 1946. Although this never occurred, in 1949, the South West Africa Affairs Act was amended to give representation in the Parliament of South Africa to whites in South West Africa, which gave them six seats in the House of Assembly and four in the Senate. This was to the advantage of the National Party, which enjoyed strong support from the predominantly Afrikaner and ethnic German white population in the territory. Between 1950 and 1977, all of South West Africa's parliamentary seats were held by the National Party.