Originating in West Africa it was brought to Haiti with slaves where it was blended with beliefs of the native Arawaks. Roman Catholic traditions have also been added since the slaves weren’t allowed to practice their own religion openly and had to disguise it in that of their French colonial masters.
Voodoo practitioners believe in a supreme creator deity who doesn’t interfere with humanity. Other deities called Lwa are able to interact with humans and can practitioners believe grant them favours. During rituals the priest is frequently possessed by the Lwa. Other things of importance are veneration of the dead, and protection from black magic.
Voodoo also has sister religions, Santeria in Cuba and Candomble in Brazil. Since its roots are in West Africa it has similarities to other religions in that area.
It gained prominence during the Haitian Revolution when a Voodoo priest Francois Mackandal used it to unite his people to overthrow the French and gain independence.
Just as Haitians have used it as to gain their freedom it has also been used for their oppression. Papa Doc Duvalier was Haiti’s dictator from 1957 to 1971 and modeled himself after the Lwa of the dead Baron Samedi. He even formed a para military organization the Tonton Macoute which was modeled after Voodoo folklore to terrorize his people. Duvalier also claimed to have killed John F. Kennedy using a curse.
Voodoo has also been popularized in Western culture, most notably the use of dolls to curse people and turning people into zombies.
While Voodoo has had a major impact on Haitian culture and history there is no empirical evidence to show that it is anything more than a myth. Possessions can be explained by the fact that powerful alcoholic concoctions are used during the ceremonies.