Ecclesia Gnostica Catholica (E.G.C.), or the Gnostic Catholic Church, is the ecclesiastical arm of Ordo Templi Orientis (O.T.O.). The E.G.C. is a Thelemic religious environment, dedicated to the advancement of Light, Life, Love, and Liberty through alignment with the Law of Thelema.
The central activity of the E.G.C. is the celebration of the Gnostic Mass, as set forth in Liber XV, written by Aleister Crowley for O.T.O. and E.G.C. in 1913. Lay membership in E.G.C. is available through baptism and confirmation. Members of O.T.O. in good standing are eligible for clerical ordination in E.G.C. Members of II° and higher are eligible for ordination as Deacon, and those who have reached K.E.W. are eligible for ordination as Priest, Priestess, or Deacon-Sacerdote. Many O.T.O. local bodies celebrate the Gnostic Mass on a regular basis. In most locations, no formal affiliation is required to attend the Mass.
A public celebration of the Gnostic Mass is one which is open to members of the public; or which is noticed in any official O.T.O. publication under the name “Gnostic Mass,” “Gnostic Catholic Mass,” “Liber XV,” or equivalent names. A private celebration of the Gnostic Mass is one at which the individual participants are all initiate members of O.T.O. of at least 0°. Private celebrations of the Gnostic Mass may be held for initiates of higher degrees as well.
For public celebrations of the Gnostic Mass, at least one of the three principal celebrating officers must be a Clerical member of E.G.C. with recognized status as Priest, Priestess, Bishop, or Auxiliary Bishop. In developing areas, this last requirement may be waived by the Primate or the Patriarch when the Gnostic Mass is being celebrated by Novices under the supervision of a Bishop.
Public celebrations of the Gnostic Mass are to be held to the highest standards of performance and fidelity to approved texts of Liber XV. The Deacon may use a script while intoning the Collects, but at all other times, officers of the Mass are expected to have their parts memorized.
The text of Liber XV, including the Collects, is not to be added to or modified without the express permission of the current Patriarch.