Control of Zanzibar eventually came into the hands of the British Empire; part of the political impetus for this was the 19th century movement for the abolition of the slave trade. Zanzibar was the centre of the Arab slave trade, and in 1822, the British consul in Muscat put pressure on Sultan Said to end the slave trade. Said came under increasing pressure from the British to abolish slavery, and in 1842 the British government told the Zanzibari ruler it wished to abolish the slave trade to Arabia, Oman, Persia, and the Red Sea. In 1890 Zanzibar became a protectorate (not a colony) of Britain. This status meant it continued to be under the sovereignty of the Sultan of Zanzibar. On 10 December 1963, the Protectorate that had existed over Zanzibar since 1890 was terminated by the United Kingdom. The United Kingdom did not grant Zanzibar independence, as such, because the UK had never had sovereignty over Zanzibar. Rather, by the Zanzibar Act 1963 of the United Kingdom, the UK ended the Protectorate and made provision for full self-government in Zanzibar as an independent country within the Commonwealth. Upon the Protectorate being abolished, Zanzibar became a constitutional monarchy under the Sultan. However, just a month later, on 12 January 1964 Sultan Jamshid bin Abdullah was deposed during the Zanzibar Revolution. The Sultan fled into exile, and the Sultanate was replaced by the People's Republic of Zanzibar and Pemba, a socialist government led by the Afro-Shirazi Party (ASP). Over 20,000 people were killed and refugees, especially Arabs and Indians, escaped the island as a consequence of the revolution. In April 1964, the republic merged with mainland Tanganyika. This United Republic of Tanganyika and Zanzibar was soon renamed, blending the two names, as the United Republic of Tanzania, within which Zanzibar remains a semi-autonomous region. The people of Zanzibar are of diverse ethnic origins. The first permanent residents of Zanzibar seem to have been the ancestors of the Bantu Hadimu and Tumbatu, who began arriving from the African Great Lakes mainland around AD 1000. They belonged to various mainland ethnic groups and on Zanzibar, generally lived in small villages. They did not coalesce to form larger political units. During Zanzibar's brief period of independence in the early 1960s, the major political cleavage was between the Shirazi (Zanzibar Africans), who made up approximately 56% of the population, and the Zanzibar Arabs, who made up approximately 17%.