Michael Aquino joined the Church of Satan in 1969, while he was in the US Army as a psychological operations specialist. Aquino became a priest in the Church in 1970, and was promoted to the level of Magister IV°, the highest ranking below High Priest (held by C of S founder Anton LaVey). In 1975, LaVey made a decision to sell priesthoods in the Church of Satan for cash, a move that alienated many existing members and officials. As a direct result of LaVey's announcement, Aquino and 28 fellow Church of Satan members left the group and founded their own church, the Temple of Set 2 . Aquino lists the number of members at closer to 100. He wrote The Book of Coming Forth By Night, supposedly with help from Set himself, declaring the need for a religion fulfilling individual potential through the Black Arts.
Aquino left the Church of Satan because of personal differences with LaVey as well as theological differences 3 . Aquino felt that LaVey was using the Church for his own personal gain - LaVey often made use of sensationalism to promote the Church. The two also differed in a deeper philosophical sense - LaVey felt that Satan was merely a symbol of strength and defiance, while Aquino belived in the literal manifestation of the god Satan (or the ancient Egyptian god Set, from which the Christian Satan is derived). The Temple of Set never gained the notorioty of the Church of Satan, largely because it was a more secretive organization from the start. The newly founded group became a non-profit church in 1975 and became exempt from federal and state taxes the same year.
Due to the tendency of the Temple of Set to avoid publicity, not much is known about their subsequent history. One major change has happened in the hierarchy of the Temple of Set in recent years. Michael Aquino stepped down as the High Priest in 1996, and has been succeeded by Don Webb. While the possibility of a philosophical change has been hinted at 4 , it is not clear what any such changes would be. Due to the inclination of the Temple of Set toward individuality as opposed to unity under leadership, it seems unlikely that a change of Head Priest would considerably alter the group's methodology.