VATICAN CITY (AP) — With all the pomp, drama and solemnity that the Catholic Church can muster, 133 cardinals began the centuries-old ritual to elect a successor to Pope Francis, celebrating a morning Mass on Wednesday before opening the most geographically diverse conclave in the faith’s 2,000-year history.

The dean of the College of Cardinals, Cardinal Giovanni Battista Re, presided over the service, urging the voters to set aside all personal interests and find a pope who prizes unity. The world today needs a leader who can awaken consciences, he said.

From the altar of St. Peter’s Basilica, Re prayed that they can agree “on the pope that our time needs” as he offered a final set of marching orders before the cardinals enter the Sistine Chapel later Wednesday to begin the secret voting.

Hailing from 70 countries, the cardinals are being sequestered from the outside world, their cellphones surrendered and airwaves around the Vatican jammed to prevent all communications until they find a new leader for the 1.4 billion-member church.

Francis named 108 of the 133 “princes of the church,” choosing many pastors in his image from far-flung countries like Mongolia, Sweden and Tonga that had never had a cardinal before.

His decision to surpass the usual limit of 120 cardinal electors and include younger ones from the “global south” — often marginalized countries with lower economic clout — has injected an unusual degree of uncertainty in a process that is always full of mystery and suspense, with smoke signals telling the world if a pope has been elected or not.

Many cardinals hadn’t met one another until last week and lamented they needed more time to get to know one another, raising questions about how long it might take for one man to secure the two-thirds majority, or 89 ballots, necessary to become the 267th pope.

“Wait and see, a little patience, wait and see,” said Cardinal Mario Zenari, the Vatican’s ambassador to Syria as he arrived for the final day of pre-vote discussions.

A final Mass, then ‘All out’

The cardinals began the day by participating in the Mass in St. Peter’s Basilica, attended by Vatican officials and the public. The 91-year-old dean of the college, Re, prayed for cardinals to find the wisdom, counsel and understanding to elect a worthy new shepherd.

Wearing bright red vestments, the cardinals processed down the central aisle of the basilica as the Sistine Chapel’s boys’ choir sang. They took up their seats around the main altar, which lies above the traditional burial place of St. Peter, considered to be the first pope.

Re had presided at Francis’ funeral, delivering a heartfelt sermon recalling history’s first Latin American pope and the reforming 12-year papacy he oversaw.

At 4:30 p.m. (1430 GMT; 10:30 a.m. EDT) the cardinals walk solemnly into the frescoed Sistine Chapel, chanting the meditative “Litany of the Saints” and the Latin hymn “Veni Creator,” imploring the saints and the Holy Spirit to help them pick a pope.

Once there, they pledge to maintain secrecy about what is about to transpire and not to allow “any interference, opposition or any other form of intervention” from outsiders to influence their voting.

Standing before Michelangelo’s vision of heaven and hell in “The Last Judgment,” each cardinal places his hand on the Gospel and swears to carry out that duty.

The awesomeness of the chapel’s frescoes, and Michelangelo’s in particular, is meant to remind the cardinals of the weighty responsibility they bear. In his regulations for the conclave, St. John Paul II wrote that in the Sistine Chapel, “everything is conducive to an awareness of the presence of God, in whose sight each person will one day be judged.”

After the cardinals take their oaths, a senior cardinal delivers a meditation. The master of papal liturgical ceremonies, Archbishop Diego Ravelli, calls out “Extra omnes,” Latin for “all out.” Anyone not eligible to vote then leaves and the chapel doors close, allowing the work to begin.

The cardinals don’t have to take a first vote on Wednesday, but they usually do. Assuming no winner is found, the Vatican said black smoke could be expected out of the Sistine Chapel chimney at around 7 p.m.

The cardinals retire for the night and return Thursday morning. They can hold up to two ballots in the morning and two in the afternoon until a winner is found.

While cardinals this week said they expected a short conclave, it will likely take at least a few rounds of voting. For the past century, it has taken between three and eight ballots to find a pope. John Paul I — the pope who reigned for 33 days in 1978 — was elected on the third ballot. His successor, John Paul II, needed eight. Francis was elected on the fifth in 2013.

Lobbying before the conclave

While the cardinals are supposed to resist any “secular” influences in their choice, such lobbying abounded in Rome in the days before the conclave as various groups reminded cardinals of what ordinary Catholics want in a leader.

Young Catholics penned an open letter reminding cardinals that there is no church without young people, women and the laity. Conservative Catholic media slipped cardinals copies of a glossy book containing their assessments of contenders. Survivors of clergy sexual abuse warned cardinals that they would be held accountable if they failed to find a leader who will crack down on decades of abuse and cover-up.

Advocates for women’s ordination were sending pink smoke signals over the Vatican to demand that women be allowed to be priests, so they too can vote in a conclave.

Lisette Herrera, a 54-year-old tourist from the Dominican Republic, was deeply moved to find herself by chance in Rome as the conclave began. She decided Wednesday morning to skip the Spanish Steps and Trevi Fountain and pray instead in St. Peter’s Square.

“I’m praying to the Holy Spirit for a young pope who would stay with us for a long time,” she said. “I don’t believe in conclave politics, I just feel that the Holy Spirit is here and that’s all we need to know.”

Challenges facing a new pope

There are any number of challenges facing a new pope and weighing on the cardinals, above all, whether to continue and consolidate Francis’ progressive legacy on promoting women, LGBTQ+ acceptance, the environment and migrants, or roll it back to try to unify a church that became more polarized during his pontificate. The clergy sex abuse scandal hung over the pre-conclave talks.

Since Francis chose 80% of the voters, continuity is likely, but the form it might take is uncertain and identifying front-runners has been a challenge.

But some names keep appearing on lists of “papabile,” or cardinals having the qualities to be pope.

— Cardinal Pietro Parolin, 70, is a leading Italian, by nature of his office. He was Francis’ secretary of state, the Vatican No. 2, and known to every cardinal.

— Filipino Cardinal Luis Tagle, 67, is a top candidate to be history’s first Asian pope. He had a similarly high-profile job, heading the Vatican’s evangelization office responsible for the Catholic Church in much of the developing world.

— Hungarian Cardinal Peter Erdo, 72, the archbishop of Budapest, is a leading candidate representing the more conservative wing of the church.