Giovanni Montini was born in Lombardy in 1897. He was ordained a priest in 1920, and barely three years later was assigned to serve in the office of the papal nuncio in Warsaw, Poland. After his brief stint there, Giovanni spent the rest of his career in service to the Roman Church, most especially to his mentor, Cardinal Eugenio Pacelli, later Pope Pius XII. Giovanni became co-Secretary of State in 1944, then Archbishop of Milan 10 years later. He wasn’t yet a cardinal by Pius’ death, but was elevated in 1958, soon after St. John XXIII’s election.

Pope Paul VI was an obvious choice to follow St. John XXIII, considering his closeness both with John and Pope Pius XII, and it took just six conclave ballots to make it official. Paul started his papacy by scaling back on papal pomp, donating his papal tiara to the Basilica of the National Shrine of the Immaculate Conception in Washington, D.C. and minimizing the grandiose papal coronation festivities, among other things. Paul opted to continue the Second Vatican Council -- councils are suspended automatically when a pope dies -- and saw it through to its 1965 conclusion.

As pope, Paul VI emphasized that the Church “doesn’t have a mission, it is a mission” and that the Church’s two millennia of tradition makes it “an expert in humanity.” He had a philosopher’s mind and a disciple’s heart, emphasizing that Jesus called all to lives of holiness, not just priests and religious. Paul VI reigned for 15 years and died on August 6, 1978. He was declared Venerable by Pope Emeritus Benedict XVI in 2012, was beatified by Pope Francis in 2014, and was canonized – alongside martyred Salvadoran Archbishop Oscar Romero – on October 14.

Two words: Humanae Vitae. At a time when the entire religious world outside of Catholicism was declaring artificial contraception acceptable, the question was finally posed to Paul VI. The Holy Father convened a theological commission to explore the question, and the result was, “Approve it!” The world expected Paul to do the same, but the good pope instead said, “Thanks, but no thanks,” rejecting the commission’s recommendation.

What followed was his most famous encyclical, Humanae Vitae (“Human life”), in which Paul explained his answer. Paul said that if artificial contraception became socially acceptable, as was the recommendation, the following would happen:

Prophetic mic drop. Read the document in full here.

Fun Fact: With visits to the Holy Land, the United States, Portugal (for Our Lady of Fatima’s 50th anniversary), and Turkey under his belt, not to mention sojourns to Africa and Australia, Paul VI was the first pope in history to visit five continents.