SOUTH BEND, Indiana (AP) — The Rev. Richard McBrien, a University of Notre Dame theologian known for his unabashed liberal stands on various church teachings and his popular books on Catholicism, died Sunday in his native Connecticut, according to the school. He was 78.

The often-quoted theology professor, who for nearly 50 years penned a weekly column for Catholic newspapers, courted controversy with his criticism of Pope John Paul II’s emphasis on orthodoxy, and he advocated for change. McBrien also spoke out in favor of artificial contraception, the ordination of female priests and optional celibacy for priests.

University spokesman Dennis Brown said McBrien died after a lengthy illness.

McBrien was highly sought out by reporters seeking comment about the Roman Catholic Church, and he was one of the most widely quoted members since joining the Notre Dame faculty in 1980. He also authored 25 books, the most popular of which were Catholicism, which drew criticism from church officials, along with Lives of the Saints and Lives of the Popes.

McBrien was asked in 1986, when speaking out in favor of the ordination of women, whether he feared church retribution in light of the Vatican forbidding the Rev. Charles Curran from teaching as a Catholic theologian for what the church said was his “repeated refusal to accept” certain church teachings. Curran was a professor at Catholic University of America.

“Do I look afraid to speak out?” McBrien responded.

His book, Catholicism, was criticized by U.S. bishops in 1985, and again in 1996, who said he had presented some core Catholic teachings as one view among many instead of as the authoritative views of the church. Still, several of his books were considered must-reads by many Catholic seminarians, theologians and parishioners.