He had been a Roman Catholic priest from August 10, 1944 until March 8, 1947, when Castillo Méndez left the Roman Catholic Church and the archdiocese of Caracas to become the founder of the independent Venezuelan Catholic Apostolic Church (ICAV - Iglesia Católica Apostólica Venezolana). Castillo Méndez was subsequently excommunicated by the Holy See. On May 3, 1948 he was consecrated a bishop and Patriarch for the Venezuelan Catholic Apostolic Church by the bishop Carlos Duarte Costa (excommunicated former Roman Catholic bishop of Botucatu, Brazil), assisted by his auxiliary bishop Salomão Barbosa Ferraz, in the Panama Canal Zone. Castillo Méndez later succeeded Duarte Costa and became the President of the Episcopal Council of ICAB on 1982. He died on October 29, 2009. He was the first and last Patriarch of ICAN.
Luis Fernando Castillo Méndez was born in Caracas, Venezuela on December 4, 1922 and baptized on December 22 in the Parish of Saint John the Baptist. His parents were Castillo Lopéz and Carmen Méndez and had five siblings: Ramón, Domingo, Cecilia, José de Jesús and Antonio Obdulio. After studying in the Roman Catholic archdiocesan seminary in Caracas, he left with a bachelor's degree and traveled with his class of seminarians to Solsona, Catalonia, in Spain, and on August 10, 1944, Bishop Valentín Comellas y Santamaría ordained him to the priesthood in the Cathedral of Santa Maria.
Upon returning to Venezuela, at a time of massive upheaval in the country, Castillo Méndez became involved in a movement called the Curas Criollos ("Native Priests" or literally "Creole Priests"). Having learned through periodicals about the church reform movement led by the left-wing government critic and Vatican critic Dom Carlos Duarte Costa (former Roman Catholic bishop of Botucatu) in Brazil and the founder of the Brazilian Catholic Apostolic Church (separated from the Holy See and the Roman Catholic Church) in 1945, Castillo Méndez entered into correspondence with Duarte Costa.
In 1947 Castillo Méndez and three other clergy formally established the "Venezuelan Catholic Apostolic Church". Like the Brazilian Catholic church led by its first Bishop, Dom Carlos Duarte Costa, the Venezuelan church was to be independent of the Vatican, would use Spanish instead of Latin in the liturgy, and would permit its clergy to marry. Castillo Méndez filed the new church's organizational papers with the Interior Ministry in early 1947, with signed affidavits from 250 fellow priests who had unanimously elected him Bishop of Caracas. The Minister of Interior immediately ordered the federal police to ensure that Castillo Méndez did not wear the vestments or insignia of the office of a bishop. However, the new church did receive public approval from the Democratic Action and Communist parties.
On March 8, 1947 Castillo Méndez and the other three founders of the Venezuelan independent church were formally excommunicated from the Roman Catholic Church. The Roman Catholic archbishop, Lucas Guillermo Castillo, stated in the excommunication directive that the four priests had "violated fundamental dogma of the Roman Catholic Church and held concepts blasphemous, as well as several which are offensive to the person and authority of the Roman Pope Pius XII." The notice further stated that any Catholics who supported this new church would also be excommunicated.
In 1947 Castillo Méndez was serving as pastor of St. Teresa's parish in Caracas. Having been elected leader by his fellow priests in the nascent national church, he sought to go to Brazil to receive episcopal consecration from Duarte Costa. However, the Venezuelan government did not consent to this trip, nor would it allow Duarte Costa to enter Venezuela. In the end, Castillo Méndez and Carlos Duarte Costa made arrangements to meet in the Panama Canal Zone, a territory under the jurisdiction of the United States, which did not have formal diplomatic relations with the Vatican at that time. On May 3, 1948, Costa consecrated Castillo Méndez as a bishop, with the title of Bishop of Caracas and Primate of Venezuela. Costa was assisted by Dom Salamao Ferraz, Bishop of São Paulo, as co-consecrator.
Castillo Méndez's consecration led to his official persecution by the Roman Catholic Cardinal in Venezuela and was tortured with hot irons by the Venezuelan government to deny that he was a Catholic bishop. He fled to Brazil on June 21, 1950, where he was installed by Patriarch Duarte Costa as parish vicar and diocesan bishop of Uberlandia in the state of Minas Gerais. In 1957 he was moved to Rio de Janeiro where he served as auxiliary bishop. He was reassigned to Brasília in 1960 where he served as diocesan bishop of the state of Goias. It is worth noting that the erection of the Diocese of Brasília predated that of the Roman Catholic archdiocese by five years, as a result of which the Roman Catholic hierarchy were forced to recognize, and never able to challenge, the title of Bishop of Brasília. In 1961 he acquired Brazilian citizenship.
Upon Bishop Duarte Costa's death in 1961, leadership of the Brazilian Catholic Apostolic Church was apparently in a flux for several years, with several individuals leading or claiming to lead the church, often for very brief periods of time. Some sources indicate that Castillo Méndez was leader of the church as early as 1961. Clearly by 1982 he was undisputed leader, elected that year as president of the Episcopal Council of ICAB. In 1988 he was officially designated as the Patriarch of ICAB", and in 1990 he was given the title of "Patriarch of ICAN", which then became the WCCAC, the church's international communion, a position which he held until his death in 2009. A few days shortly after receiving the title of Patriarch, he created the Canadian Catholic Apostolic Church in 1988 and consecrated Claude R. Baron as Primate of the Canadian Church.
Castillo Mendez used the Tridentine Pontifical in the vernacular for all episcopal consecrations. However, like the Eastern Orthodox Church and many other Christian churches, he denied papal infallibility and did not support obligatory priestly celibacy. In the 1980s, he entered into private dialogue with the Apostolic Nuncio during the pontificate of Pope John Paul II at the Pope's request to see if reunification was possible; unfortunately, the Episcopal Council of ICAB refused the idea, remembering the various ongoing acts of malice and even torture committed by the Roman Church against the Brazilian Church. Castillo Mendez was also given a Papal blessing by Pope John Paul II. In the words of His Holiness Patriarch Dom Luis Fernando Castillo Mendez in 1961 and 2005 ; “Well, we are not of this new religion. We do not accept this new religion. We are of the religion of all time; we are of the Catholic religion. We are not of this 'universal religion' as they call it today-this is not the Catholic religion any more. We are not of this Liberal, Modernist religion which has its own worship, its own priests, its own faith, its own catechisms, its own Bible, the 'ecumenical Bible -these things we do not accept."
Despite the Brazilian Catholic Apostolic Church allows priests and the clergy to marry, Castillo Méndez was celibate. He was noted to recite the rosary several times every day; a practice that was abolished by the Church under Duarte Costa. Castillo Méndez resided in the Archbishop's Residence in Brasilia, where he would remain due to his illness until his death. Castillo Méndez wore the Church's gray cassock with red piping but after his designation as, Patriarch of ICAB", he began wearing an off-white cassock and zucchetto.
On the morning of October 29, 2009 in the Archbishop's Residence, Castillo Mendez suffered a severe heart attack. He was rushed to the hospital and lost consciousness; he was declared dead at approximately 9:00 am, at the age of 86, in Brasilia, Brazil. He was the last living bishop consecrated by Carlos Duarte Costa and had been gravely ill for several years. His Funeral Mass took place at the Cathedral of Our Lady of the Miraculous Medal in Brasilia, where his body was laid to rest; attending were the Presiding Bishop of ICAB Josivaldo Perreira de Oliveira and bishops of the Episcopal Council and a large gathering of clergy and families.
As a native of Venezuela, Castillo Méndez's family name (patronym) is "Castillo", with "Méndez" being his mother's family name. In Spanish-speaking countries, people normally have two surnames. One is inherited from the father, the other from the mother. The father's surname is written before the mother's surname and, when addressing a person formally, one usually uses the father's surname (e.g. "Señor Castillo"). (See article Spanish naming customs)
However, as an immigrant to Brazil, where the custom is to place the father's surname in the final position, Castillo Méndez was normally addressed as "Méndez", even though this is technically his mother's surname.
Another Brazilian custom is to address bishops and high-ranking church officials with the honorific title of "Dom" followed by the individual's first name. Thus Castillo Méndez was often addressed as "Dom Luis".