More than 100 senior members of the clergy, known as cardinals, meet in the Vatican’s Sistine Chapel to cast ballots. They aren’t allowed to leave or communicate with the outside world until they’ve reached an agreement. The process can last days, weeks, sometimes years. 

The Origins

The word conclave comes from the Latin words cum and clavis, the idea being that the cardinals are kept “under lock and key” until they’ve decided on a new leader, a tradition that dates back to the 13th century. 

The conclave in the Italian city of Viterbo that followed the death of Pope Clement IV lasted from 1268 to 1271, making it the longest in history. Frustrated townspeople tore the roof off the papal palace and fed the cardinals only bread and water in an attempt to force a decision. Eventually the cardinals were ordered not to leave until they had come to an agreement. To avoid a repeat of those chaotic scenes, firm rules for papal elections were laid down in 1276. 

The Sistine Chapel was designated as the permanent location for papal enclaves in 1878. Nowadays, cardinals attending a conclave sleep in the Santa Marta residence inside the Vatican. They aren’t allowed to have any electronic devices or contact with the outside world, and make their way to the chapel every day until the conclave ends. 

The Significance

The pope has no formal say in secular matters, yet he wields considerable influence in Rome and around the world, through the Church and its 1.4 billion followers, and via the Holy See’s own diplomatic corps. 

Each pope has his own way of dealing with politics. John Paul II, a Pole, was seen as a bridge between western democracies and Eastern Europe during the Cold War, even supporting the Polish trade union Solidarity that played a major role in the downfall of communism.  

Benedict XVI, who was pope from 2005 until he resigned in 2013, was regarded as more of a theologian, with limited interest in world affairs. His successor Francis, who died on Monday, was outspoken on politics, even clashing publicly with US President Donald Trump on his plans for migration. 

In Italy, the Pope is a significant figure in national affairs, with governments of different political creeds working to maintain strong relations with the Vatican and consulting the pontiff on issues as varied as tax law or LGBTQ rights.

The Process

After the death or resignation of a pope, responsibility for Church matters passes to the Sacred College of Cardinals, whose first priority is to prepare for the next conclave. A mourning period of 15 days is usually observed before this can begin. 

The college comprises bishops and Vatican officials from all over the world, chosen personally by former popes. Each nomination is significant because it can affect the stance of the college on various matters and hence the origins and views of the next pontiff.

According to canon law, only cardinals under the age of 80 are eligible to vote. While the conclave should consist of no more than 120 electors, this limit hasn’t always been respected. In December 2024, Pope Francis appointed 21 new cardinals, taking the total to more than 130. 

Discussions and four rounds of balloting take place each day until a candidate — almost certainly one of the cardinals who is part of the conclave — receives two-thirds of votes. 

The Decision

The results of each ballot are counted aloud and noted. If no one receives the necessary votes, the ballot papers are burned in a stove near the chapel, with a chemical added to make the smoke black. Once the cardinals are finally agreed, the final-round ballots are burned with chemicals producing white smoke that emerges over the Vatican, signaling to the world that a new pope has been chosen.

The proceedings in the Sistine Chapel take place in strict secrecy, a tradition that dates from the 13th century when the papacy was an important player in European politics and major powers would try to influence the outcome, occasionally resorting to threats and bribery. The secret ballot has been maintained through the centuries in order to defend the independence and freedom of the cardinals. Even today, any leak of voting intentions before or during the conclave could be seen as an attempt to influence the outcome. 

The Roman Catholic faithful gather in St. Peter’s Square to observe the smoke signals and learn who will be their new spiritual leader. 

The dean of the Sacred College of Cardinals asks the winner of the ballot if he accepts his election. If he does, he chooses a papal name and is dressed in papal vestments before appearing at the balcony of St. Peter’s Basilica to bless the crowd and the rest of the world.