The Occultation ( Ghaybah) in Shia Islam refers to a belief that the messianic figure, or Mahdi, who in Shi'i thought is an infallible male descendant of the founder of Islam, Muhammad, was born but disappeared, and will one day return and fill the world with justice and peace. Some Shi'is, such as the Zaidi and Nizari Ismaili, do not believe in the idea of the Occultation. The groups that do believe in it differ on the succession of the Imamate, and therefore which individual is in Occultation. The Hidden Imam is still considered to be the Imam of the Time, to hold authority over the community, and to guide and protect individuals and the Shi'i community.