Clemente Domínguez y Gómez
Gregory XVII (Latin: Gregorius PP. XVII; Spanish: Gregorio XVII; born Clemente Domínguez y Gómez; 23 May 1946 – 21 March 2005), also known by the religious name Fernando María de la Santa Faz, was the first Pope of the Palmarian Catholic Church, who in this capacity, claimed to be the 263rd Pope of the Catholic Church from 6 August 1978 until his death on 21 March 2005. He was an alleged visionary, seer and mystic, who, following claimed apparitions of the Blessed Virgin Mary as Our Crowned Mother of Palmar, founded a religious order which claimed to continue the work of the Carmelites, known as the Carmelites of the Holy Face; after 1978, this order became synonymous with the Palmarian Church.
Source: Wikipedia — Clemente Domínguez y Gómez (CC BY-SA 4.0)