Pope Francis struck on Monday the most conciliatory tone towards homosexuality ever expressed by a pope, in line with the "culture of encounter" he spoke of during his triumphant visit to Brazil.

"If a person is gay and seeks God and has good will, who am I to judge?" the pope said in a remarkably candid news conference on the 12-hour flight from Rio de Janeiro to Rome.

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Francis strolled to the back of the aircraft and talked to incredulous reporters for a full hour and 20 minutes, answering delicate questions on sex scandals, the Vatican bank, divorced and remarried Catholics and the role of women in the Church.

“He took questions with no filters or limits and nothing off the record,” John L Allen, a Vatican analyst for the National Catholic Reporter, who was on board the flight, wrote on his blog.

Calling for a “theology of women” and a greater role for them in Catholic life, warning against judging gays and hinting at possible changes about banning communion for divorced and remarried Catholics, the pontiff’s comments appear to stand outside some of the Church' stricter lines.

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“He insists on dialoguing and discussing things that kept people at the margins in Catholic life in the past 34 years -- gender and sexuality among them,” Steven M. Avella, a priest of the Archdiocese of Milwaukee and a professor of history at Marquette University, told Discovery News.

“Although focused on priests, his reaction to gays and lesbians, was I believe directed to all people," Avella said. "This makes perfect sense to any man or woman of good pastoral instincts -- of course the first reaction of any loving pastor is mercy, love and the suspension of judgment. His comments on women too seemed to open a door seemingly closed tight by John Paul II."

Although Francis appears to be the first pontiff in decades to reach beyond traditional Catholics, he's not the only pope who has stepped outside conservative parameters.

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In his Sept. 10, 1978 Angelus address, John Paul I, “the smiling pope,” boldly challenged the traditional vision of theology stating that God had a "feminine nature" and was "more of a mother than a father."

He died suddenly 18 days later, only 33 days after being elected pope, of a heart attack. Pointing to intrigues between conservatives and liberals in the Roman Catholic Church hierarchy, conspiracy theories flourished suggesting he was the victim of foul play.

Pope Francis leads his first general audience at John Paul VI Hall in the Vatican.Alessandra Benedetti/Corbis

Further back in history, other popes took actions that have moved theological and pastoral discussion forward.

“Pius XI comes to mind with his refusal of the ‘prisoner of the Vatican’ mentality of previous popes who rejected the formation of the Italian state,” Avella said.

Pius XI (1857-1939) was indeed responsible for one of the most important events in the history of the Vatican on Feb. 11, 1929 -- the signing of the Lateran Treaty between the pope and King Emmanuel III of Italy. The agreement ended almost 60 years of papal isolation, when the popes even refused to appear at the balcony on Saint Peter’s Square, allowing the Vatican and Italy to recognize each other as sovereign nations.

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Other popes, such as Leo XIII (1810–1903), reset the parameters of discussion on such issues as economic justice. In his 1891 revolutionary Rerum novarum, the first major encyclical on capitalism and social issues, Leo XIIII defended private property, as well as the rights of workers to form associations for better treatment.

Pope John XXIII (1881-1963), who soon will be made saint along with John Paul II, recommended putting aside doctrinal issues and focusing on the modern world’s trends when he opened the Second Vatican Council on Oct. 11, 1962.

“As Father John O'Malley S.J. noticed, John XIII's remarks gave a tenor and direction to Vatican II that was not expected at the time," Avella said. "It was free of anathemas, it had a more conciliatory and dialogical tone than previous councils and broke new ground in such topics as relations with the Jews, religious liberty and the role of the church in the modern world."

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But liberal and conservative are relative terms in the Catholic Church, after all.

According to Thomas F. X. Noble, professor of history at Notre Dame and an expert on the history of the papacy, the concept also applies to Pope Francis, whose directness and humble style continue to win the hearts of millions.

“On questions of economic justice, Francis is, in secular terms, radical,” Noble told Discovery News. "He says we need a deeper theology for understanding women. But he says the door is closed to the ordination, so where this goes will be revealed in time."

As for Francis’s comment on gays, Noble found it “a remarkable pastoral statement.”

“Yet we have no policy. Is this conservative? Traditional? Simply Catholic? I think we are in for some surprises in the next year or two. In the end, Francis will baffle the commentariat the way John Paul II did,” Noble said.