Today in 1494. the first conclave to be held in the Sistine Chapel opened. Concerns about political interference in the election of a pope had led the great reforming Pope Gregory X to issue a decree during the Second Council of Lyons that the cardinal electors should be locked in seclusion cum clave (Latin for 'with a key') and not permitted to leave until a new pope had been elected.
Since the time of St Peter, the first bishop of Rome, the Pope, like other bishops, was chosen by the consensus of the clergy and laity of the diocese. For a long while you did not even have to be a priest to be elected as a bishop, although once accepted, sacramental ordination would follow in due course. For the first eight centuries of the church it was even possible for a lay man to be elected to the See of Rome, a famous example was when Ambrose was elected Bishop of Milan in the fourth Century was still catechumens, i.e in the process of being received into the church. (see pod of Apr 24 to hear more about Ambrose, and his influence on Augustine)
After the disastrous election of Antipope Constantine II, Pope Stephen III held the synod of 769, which decreed that only a cardinal priest or cardinal deacon could be elected, specifically excluding those that are already bishops. Constantine was condemned and expelled from the Church during the Lateran Council of 769. Hi election had been secured by force of arms, with the support of Tuscan Nobleman. He was depose the following spring and is now considered an antipope. 300 years later the College of Cardinals was designated the sole body of electors. In 1970, Pope Paul VI limited the electors to cardinals under 80 years of age and at the moment conclaves are held following procedures laid out by Pope John Paul II and amended by Pope Benedict XVI. Currently a two-thirds majority vote is required to elect a new pope.
It is thought that the first forced seclusion of cardinals, may have taken place in Perugia in 1216. Forty years later in 1269, when the forced seclusion of the cardinals alone failed to produce a pope, the city of Viterbo refused to send in any materials except bread and water. When even this failed to produce a result, the townspeople removed the roof of the Palazzo dei Papi in their attempt to speed up the election. Gregory laid down clearer rules to make sure that they Cardinals were to be secluded in a closed area and not accorded individual rooms. No cardinal was allowed, unless ill, to be attended by more than two servants. Food was supplied through a window to avoid outside contact. After three days of the conclave, the cardinals were to receive only one dish a day; after another five days, they were to receive just bread and water. During the conclave, no cardinal was to receive any ecclesiastical revenue.
Todays conclave was the first in the Sistine Chapel, with the voting taking place in front of Michelangelo's impressive fresco of the Final Judgement (see pod of Mar 6) Each cardinal elector writes the vow that I call as my witness Christ the Lord who will be my judge, that my vote is given to the one who before God I think should be elected. The signature and motif of the elector covered by two folded-over parts of the ballot paper was added by Gregory XV in 1621, to prevent anyone from casting the deciding vote for himself. Cardinal Pole of England refused to cast the deciding vote for himself in 1549 (and was not elected), but in 1492 Cardinal Borgia (Pope Alexander VI) did cast the deciding vote for himself, At the beginning of the conclave, the master of papal liturgical celebrations orders all individuals other than the cardinal electors and conclave participants to leave the Chapel. Traditionally, he stands at the door of the Sistine Chapel and calls out: "Extra omnes!" ('Outside, all [of you]'). He then closes the door. Beginning in the early 1800s, the ballots used by cardinals were burned after each ballot to indicate a failed election. The lack of smoke instead would signal a successful election. Since 1914, black smoke (fumata nera) emerging from a temporary chimney installed on the roof of the Sistine Chapel indicates that the ballot did not result in an election, while white smoke (fumata bianca) announces that a new pope has been chosen.