Michael Aquino joined the Church of Satan in 1969 as an Army officer with a serious intellectual bent, and rose within a few years to lead one of its most active chapters. By the mid 1970s he had grown uneasy with the direction Anton LaVey was taking the organization, particularly a restructuring that sold priesthood credentials for a fee, a move Aquino read as trading the church's substance for its income. On June 10, 1975, he resigned.
What followed, in Aquino's own account, was not a slow founding but a sudden one. Working alone that same month, he describes entering a working with the ritual formula from LaVey's own Satanic Bible and receiving, in response, a text rather than a feeling: a document he did not compose so much as transcribe, presented to him by a being identifying itself not as Satan but as Set, the god behind Satan's borrowed imagery in the first place. He called it The Book of Coming Forth by Night, and treated its arrival as the actual founding moment of a new order rather than a personal vision to keep private.
Within weeks he had gathered the members loyal to him and announced the Temple of Set, positioning it explicitly as a break from LaVeyan Satanism rather than a splinter faction still practicing the same religion under new management. The manner of the founding, a text received rather than written, set the order's self-understanding for everything that followed.