Ecclesia Gnostica Catholica (EGC), or the Gnostic Catholic Church, is the ecclesiastical arm of Ordo Templi Orientis (OTO), an international fraternal initiatory organization devoted to promulgating the Law of Thelema. Thelema is the religious and philosophical system established by Aleister Crowley in 1904. Its name is somewhat confusing, as the term Catholic is used in its original sense of "universal", rather than in reference to the various Christian churches using that word in their names.

The chief function of EGC is the performance of the Gnostic Mass (Liber XV), a eucharistic ritual written by Crowley in 1913. The structure of the Mass is influenced by the rite of the Russian Orthodox Church; its content draws from the symbols and texts of Thelema. Its most notable divergence from similar rites of other churches is that both a Priest and a Priestess officiate, the latter sitting unclothed on the altar during most of the ceremony. In addition to the Mass, baptism, confirmation, marriage, and last rites are offered by EGC.

Crowley described the Gnostic Mass as "the central ritual of the OTO, both public and private". It is the single most commonly performed ritual at OTO bodies, with many locations celebrating the Mass monthly or more frequently. Most OTO bodies make some or all of these celebrations open to interested members of the public, so the Mass is often an outsider's first experience of the OTO.

EGC has a hierarchical structure of clergy, assisting officers, and laity which parallels the degree structure of the OTO initiatory system. Before 1997, the two systems were more loosely correlated, but since then there have been strict rules concerning minimum OTO degrees required to serve in particular EGC roles.

References

Ordo Templi Orientis, US Grand Lodge (2004) Ecclesia Gnostica Catholica (http://oto-usa.org/egc.html). Retrieved January 3, 2005.