Much of Africa's cultural activity centers on the family and the ethnic group. Art, music, and oral literature serve to reinforce existing religious and social patterns. The Westernized minority, influenced by European culture and Christianity, first rejected African traditional culture, but with the rise of African nationalism, a cultural revival occurred. The governments of most African nations foster national dance and music groups, museums, and to a lesser degree, artists and writers. Over the centuries, peoples from other parts of the world have migrated to Africa and settled there. Historically, Arabs have been the most numerous immigrants. Starting in the 7th century ad, they crossed into North Africa from the Middle East, bringing the religion of Islam with them. A later movement of Arabs into East and Central Africa occurred in the 19th century. read on.