William Breeze, also known by his neo-Gnostic bishop title of Tau Silenus (born August 12, 1955) is an American author and publisher on magick and philosophy. He is the Sovereign Patriarch, or supreme governing cleric, of Ecclesia Gnostica Catholica (E.G.C.), the liturgical arm of Ordo Templi Orientis (O.T.O.), of which he is the current Outer Head of the Order (OHO), also known as Frater Superior, as well as caliph, the order's international leader. In this capacity he is a leading editor of the occult works of Aleister Crowley, the founder of the philosophy and religion of Thelema, who is regarded as its prophet.