About half of Tanzania's population practices Christianity, about one-third follows Islam, and there are numerous Hindus and Sikhs in the Indian communities. Christianity was introduced into Tanzania when a Roman Catholic mission was established in the coastal city of Kilwa during the Portuguese occupation from 1505 to 1513. By the late 1840s, missionaries and white colonizers had established Catholic and Protestant missions, and there are still a number of mission churches run by international religious groups. Today, Christian denominations are operated under an umbrella organization, the Christian Council of Tanzania, which was founded in 1934.
The mainly Islamic coast has maintained contact with Muslims from the Arabian Peninsula since the 14th century, when it was part of the trade route around the Indian Ocean. Today, Tanzania's Muslim affairs are managed by The National Muslim Council of Tanzania, founded in 1969 and which oversees the mainland, while the Supreme Muslim Council, formed in 1991, administers the islands. Visitors to Zanzibar and the other islands, which are very conservative, must take precautions not to offend Muslims: Cover up bare flesh, make no public displays of affection, and don't eat and drink in public during the annual Ramadan fast.
Indigenous beliefs are varied but most involve a belief in an eternal god and spiritual forces, which are often ancestral spirits, who assist in day-to-day life. Many Tanzanians will give their children a name from a grandparent or great-grandparent in addition to a Christian or Islamic name, which reflects a relationship with the ancestral spirit world. Furthermore, many Tanzanians seek the help of diviners and traditional healers in cases of sickness and misfortune.
