The Rastafari movement or Rasta is a new religious movement that arose in the 1930s in Jamaica, at the time a country with a predominantly Christian culture where 98% of the people were the black descendants of slaves. Its adherents worship Haile Selassie I, Emperor of Ethiopia (ruled 1930–1974), as God incarnate, the Second Advent, or the reincarnation of Jesus. Members of the Rastafari movement are known as Rastas, or Rastafari. The movement is sometimes referred to as "Rastafarianism", but this term is considered derogatory and offensive by some Rastas, who, being highly critical of isms which they see as a typical part of Babylon culture, dislike being labelled as an "ism" themselves.
The Rastafari movement encompasses themes such as the spiritual use of cannabis and the rejection of western society, called Babylon (from the metaphorical Babylon of the Christian New Testament). It proclaims Africa (also "Zion") as the original birthplace of mankind, and from the beginning of the movement the call to repatriation to Africa has been a central theme. Rasta also embraces various Afrocentric and Pan-African social and political aspirations, such as the sociopolitical views and teachings of Jamaican publicist, organizer, and black nationalist Marcus Garvey (also often regarded as a prophet). Another theme is Royalty, with Rastas seeing themselves as African royalty and using honorifics such as Prince or King in order to give royalty to their names.
Rastafari is not a highly organized religion; it is a movement and an ideology. Many Rastas say that it is not a "religion" at all, but a "Way of Life". Many Rastas do not claim any sect or denomination, and thus encourage one another to find faith and inspiration within themselves, although some do identify strongly with one of the "mansions of Rastafari" — the three most prominent of these being the Nyahbinghi, the Bobo Ashanti and the Twelve Tribes of Israel.
Source: Wikipedia, "Rastafari movement", available under the CC-BY-SA License.