About Fr. Mariani





Father John Guilbert Mariani was born 1947 in Palo Alto, California. His mother, Dame Mary Frances Mariani-Bigler, the former Mary Frances Guilbert, and his late father, Paul Andrew Mariani Jr., brought up seven children. His family were pioneers in the California dried fruit industry, headquartered in the Santa Clara Valley.




He was graduated from St. Leo the Great Grammar School in San Jose, and Holy Cross Abbey Preparatory School in Colorado, where he served as class president.  He studied religion at Mont La Salle in Napa, and received a BA in Art History at Saint Mary's College, Moraga, California in 1971.  He studied graduate philosophy and theology at St. Albert the Great for another year and a half in Berkeley, California. Until 1992 he worked as Vice-president of the Mariani Group of Companies, where he received the National ADDY Award for design. In San Jose, he served on the Board of Directors of the San Jose Symphony and the San Jose Museum of Art. He has lived in London, Paris, Rome, Barcelona, and Indonesia. He resumed his studies of Philosophy at St Patrick's Pontifical Seminary in Menlo Park, California.  He received his Bachelor of Theology and Masters of Divinity in 1996 at Mount Saint Mary's College in Emmitsburg, Maryland. He studied Spiritual Theology at the Angelicum Pontifical University in Rome, and was ordained for the Society of Our Lady of the Most Holy Trinity by Bishop Pierre DuMaine in 1997. After assignments in Texas and England, he was assigned in 1999 as Chaplain to Domus Pacis, the World Apostolate of Fatima Guest House, in Fatima, Portugal. Father Mariani is canonically incardinated in the African Diocsese of Saõ Tome e Principe as Chancellor to the Diocese in Europe and the Americas, seated at Casa Alta Royal Lodge, where he also works as its present Rector, established under the authority of the Bishop of Fatima/Leiria.



Canonical Affiliation

Fr. Mariani is a priest of the African Diocese of São Tomé e Principe and is its Chancellor in Europe.




List of Boards, Academies, Organizations, Societies, Brotherhoods, Associations:

  • Chaplain of the Foreign Delegation of Dynastic Orders to the Royal House of Portugal
  • Chaplain of the Royal Brotherhood of the Most Holy Miracle (Santarém)
  • Patron of the Vatican Museums, Portuguese Chapter Vice-president
  • Chaplain of the Duke of Braganza's Own Regiment Legion of Frontiersmen (UK) 25th Rifle Battalion Reserves
  • Confraternity of the Holy Grail in the Cathedral of Valencia, member of Honour
  • Chaplain of the Italian National Institute of Honour Guards of the Royal Tombs and Pantheon
  • Chaplain of the Royal Portuguese Guards
  • Royal Confraternity of the Blessed Sacrament, Grand Cross
  • Member, Napoleon I Institute of Historic-Military Studies
  • King Kegeli Society (Fellow)
  • Chaplain protector Royal Car Club of King Carlos I
  • Royal Confraternity of Wine and Gastronomy of Ourem
  • Board Member of Oureana Foundation
  • Portuguese Ex Libris Academy
  • Confraternity of the Holy Scapular
  • Ex Board Member San Jose Symphony
  • Ex Board Member San Jose Museum of Art





List Orders of Knighthood, Dynastic Orders, & Nobiliary Associations:


  • Chaplain of the Order of Malta
  • Royal Order of Vila Viçosa of Our Lady of Conception de Vila Viçosa
  • Chaplain of the Foreign Delegation of The United States, Canada, Australia, Ireland, and Great Britain, of the Royal Order of Saint Michael of the Wing, Grand Cross
  • Chaplain Royal Order of Sts Maurice and Lazarus (House of Savoy)
  • Imperial Solomonic Order of Merit
  • Order of the Crested Crane (Rwanda)
  • Order of the Dragon of Anam (Vietnam)
  • Chaplain of the Order of the Tunic, Grand Cross (Georgia)
  • Chaplain of the Royal Order of Grue, Grand Cross
  • The Venerable and Noble Pontifical Archconfraternity of Sts. Peter and Paul (Italy)
  • Chaplain/Confrater of the Noble Company of Knights Arbusters of St. Felipe and St. James (Spain)
  • Imperial Order of the Star of the Ethiopian Empire, Commander with Star
  • Order St. Thomas Apostle, Grand Cross with star(Sao Tomé and Principe).