Pope John XXIII imparts his Apostolic Blessing upon the Fathers of the Roman Catholic Ecumenical Council at the closing ceremony of the first phase on Dec. 8, 1972. (AP Photo/Mario Torrisi)

1962: Pope John XXIII

After four years at the head of the Roman Catholic Church, Pope John XXIII convened an Ecumenical Council called Vatican II in 1962. This rare event gathered together the church's global leaders in an attempt to address relations between the Roman Catholic Church and the modern world.

More than halfway into the 20th century, Pope John looked around and realized that the world was undergoing rapid change. Progress in science and the economy, as well as changing moral values and politics, were affecting the way people thought, acted, and lived together. The goal of Vatican II was to realign the church, essentially making it more Catholic and less Roman. In doing so, Pope John stretched out a hand of friendship to non-Catholics and made a bid for Christian unity.

It was Pope John's historic gesture that TIME said "made the biggest individual imprint on the year."

Pope John even beat out President Kennedy, who that year brought a successful resolution to the Cuban Missile Crisis, a Cold War turning point.

At the time, American theologians said Pope John's impact could be as "profound as anything since the days of Martin Luther." Indeed, he was one of the most popular popes of modern times, whose warmth, simplicity, and charm won the hearts of Catholics, Protestants, and non-Christians alike, wrote TIME.

Pope John Paul II touches hands with the crowd in Oropaa, Italy, during a private vacation in July, 1989. (REUTERS/Luciano Mellace)

1994: Pope John Paul II

By 1994 — more than 15 years into his papacy and about 10 years from his end — John Paul was hitting his stride.

He was so admired the world over that a visit could inspire rock-star adulation from the crowd. He was a vocal and determined Pope, keen on spreading his message far and wide, which he did regularly from the pulpit but also in his best-selling book Crossing the Threshold of Hope. But it was his will, which he controversially imposed upon the world in September 1994, that would set him apart in history.

At the U.N.'s International Conference, John Paul and his emissaries helped defeat a U.S.-backed proposition that the Pope feared would encourage abortions worldwide. It was a controversial move and one the Pope was criticized for, but he defended his actions as necessary for the good of the church. In an interview with TIME he said, "The Pope must be a moral force."

It was this steadfast rectitude that TIME held aloft. "In a year when so many people lamented the decline in moral values or made excuses for bad behavior, Pope John Paul II forcefully set forth his vision of the good life and urged the world to follow," wrote TIME.

Pope Francis washes the foot of a prisoner on March 28. Two women were among the 12 people whose feet the pope washed and kissed at a transitional ceremony at a youth prison in Rome, marking the first time a pontiff has included females in the rite. (REUTERS/Osservatore Romano)

2013: Pope Francis

Having only inherited the papacy on March 13, Pope Francis is still settling into his role. But in that brief time, Francis has already stepped out of the mold set for him by his predecessors.

The first non-European pope in 1,200 years, Francis has proved to be remarkably humble and welcoming, whereas other popes have remained somewhat distant.

Francis came to power at a precarious time for the church, which has been rocked by a child sex abuse scandal that will undoubtedly weigh heavy on his zucchetto in the coming years.

While his answers on issues of women's rights, abortion, and gay marriage have been the church's, Francis has shown a level of understanding — a plea to respect the goodness of individuals over the label bestowed upon them — that has endeared him to millions. In this respect, Francis offers a way for the divided church to agree to disagree on these controversial issues while still following through with its mission to spread mercy. And it is this potential for change and action that TIME honored.

"'Argue less, accomplish more' could be a healing motto for our times. We have a glut of problems to tackle. Francis says by example, Stop bickering and roll up your sleeves. Don't let the perfect be the enemy of the good — and important thing for the world to hear, especially from a man who holds an office deemed infallible," wrote TIME.