In the early 1900s, Marcus Garvey–controversial Jamaican-born writer, orator, organizer, Black Nationalist, Pan-Africanist and proponent of the “back to Africa” movement which urged diaspora Africans to return to the continent–told diaspora Africans to “Look to Africa, where a black king shall be crowned, for the day of deliverance is near.” When Haile Selassie (born Tafari Makonnen), legendarily a direct descendant of the biblical King Soloman and the Ethiopian Queen of Sheba, became emperor of Ethiopia in 1930, many Jamaicans saw his ascension as the fulfillment of Garvey’s prophecy. Jamaican followers of “Ras Tafari” (head/leader Tafari) welcomed him as the Messiah and developed devotional practices that celebrated him as a divine messenger of God (“Jah”).
In the 1970s Bob Marley’s reggae music brought Rastafari to the international masses and inspired the aesthetic of Rastafarianism to become widespread–specifically, the symbolic wearing of red, yellow/gold and green and the twisting of the hair into dreadlocks (a practice existed long before Rastas). Today, while most religious Rastafarian communities are still based in Jamaica (though there are Rasta settlements in Ethiopia, like Shashamane), Rastafari as a secularized spiritual movement has spread across national borders and even racial lines.
Wikipedia on Rasta/Rastafarians | Biography of Marcus Garvey | Haile Selassie: Messiah or traditional African monarch? | ‘The Mansions of Rastafari,” including the Nyabinghi | The parallels between Rastafarianism and Judaism