Several kingdoms have existed in the area of today's Uganda, the largest being the Buganda, which has been restored recently. Uganda was a British protectorate from 1888 onwards. It recovered its independence in 1962. From 1966 to 1986, the country suffered coups and dictatorial regimes, the worst of which was Idi Amin's rule which was brought to an end in 1979, with the help of an intervention by Tanzania. Hundreds of thousands of Ugandans were killed, among them Anglican Archbishop Luwum, and the economy was wrecked. Uganda has regained political stability, except for the rebellion of the Lord's Army in the north, which forces thousands of children to be soldiers. The country has been involved in the conflicts in neighbouring east Congo, supporting some of the rebel factions, and in southern Sudan. Uganda's economy is based on agriculture. The country has fertile soils and considerable natural resources. The main export crop is coffee. Christianity came to Uganda in the 19th century. Among the first converts, several were martyred by a king who opposed the new religion. The two largest churches, Catholic and Anglican, form the Joint Christian Council, together with the Ugandan Orthodox Church which is part of the Patriarchate of Alexandria. Among the Protestant and independent churches, Pentecostal churches and groups form a sizeable part. More than half of them belong to the Pentecostal Assemblies of God. Uganda is one of the leading countries in Africa in the struggle against HIV/AIDS.