The Ordo Templi Orientis (O.T.O.) was founded by an Austrian named Carl Kellner. As a member of the Freemasons and the Rosicrucian Order, Kellner hoped to use customs from both orders in the O.T.O. The O.T.O. spread the beliefs of a religion known as Thelma, which promotes personal uniqueness and independence. Kellner worked together with Theodore Reuss to establish an order similar in organization to Freemasonry with teaching similar to the Rosicrucian Order.
The O.T.O. was similar to Freemasonry in principle as women were not allowed to be members. In the O.T.O, Kellner hoped to change this principle to allow women to join his new Order. After working to revive the Order of Illumitati, Reuss directed his attention to Kellner and establishing the O.T.O.