VATICAN CITY - Tomorrow, 115 cardinals of the Roman Catholic Church will sequester themselves in the Vatican's Sistine Chapel for the beginning of the faith's most private and perhaps most important ritual, the election of a new pope.

They will dress in their traditional scarlet cassocks and hats, and, after a Mass and lunch, will file one by one into the 15th-century sanctuary, chanting an ancient ode to God.

They will have surrendered cell phones, radios and any other links to the outside, and they will swear on the Gospels never to speak of the proceedings about to transpire. Once inside, the cardinals will hear speeches from Vatican officials describing the state of the church and their immediate duties, then they will dismiss the speakers and all others not eligible to vote.

A cardinal will rise, walk to the chapel door and lock it, and the conclave will officially begin.

"What it comes down to is that these cardinals are looking for someone who can serve as a successor to [St.] Peter," said John Wauck, a Vatican expert teaching at Rome's Pontifical University of the Holy Cross. "They are looking for someone they can imagine calling 'your holiness,' the next vicar of Christ, servant of the servants of God."

Shaping the future

Beneath the history and pageantry is a process that may well shape the future of Catholicism for a generation or more. The man who appears in white on the Vatican balcony at the conclave's conclusion will have entered the chapel as merely one of many church officials, but will emerge as the leader and ideological linchpin of by far the largest Christian denomination. It is a position of global stature - and a job, Vatican insiders say, that few of the church's cardinals are likely to covet.

"Frankly, anybody who wants to be pope is out of his mind," said Archbishop John P. Foley, president of the Vatican's Pontifical Council for Social Communications, and who has worked at the Vatican for 21 years. "It's a living martyrdom."

The group of cardinals in the conclave will be the largest and most geographically diverse since the Church, in 1179, recognized cardinals as the sole electors of a pope. Although 117 cardinals are eligible to participate, two are unable to travel because of illness.

Though only two of the men present participated in the conclave that chose Pope John Paul II, the cardinals will all know what is expected.

Tradition rules

Only one vote may be conducted tomorrow, followed by four each day until a new pope is selected. Tradition dictates that each cardinal pen the name of a candidate on a rectangular paper ballot, fold it in half lengthwise, then rise one at a time and walk to the Sistine Chapel's altar. They will drop their ballots into an urn - Pope John Paul did away with the traditional chalice during his tenure - then recite a declaration of the vote's authenticity.

Three cardinals, chosen at random, will count the ballots, and one will read the names aloud if the number of votes corresponds to the number of cardinals present. As each ballot is read, the cardinal will pierce it with a needle and thread the ballots together, a tradition designed to ensure that none of them is lost or saved. A second set of three cardinals then recounts the ballots.

Smoke signals

If two-thirds of the cardinals have not agreed on a single candidate, the ballots are burned, along with any notes or evidence of the vote. Traditionally, straw was added to the fire to create black smoke to signal to the crowds outside that no pope had been chosen. When a successor was selected the ballots were burned by themselves, yielding white smoke to signal the conclave's success. This year the cardinals will have bells rung to announce the pope's election.

The cardinals will continue voting four times a day - twice in the morning, twice in the evening - until that two-thirds majority is reached. If no pope is elected after the third day, they may choose to rest for a day of reflection before resuming the schedule, taking an additional rest after each group of seven unsuccessful ballots.

The pattern can continue twice more - seven votes, optional break, seven votes, optional break - before a provision created by Pope John Paul allows the cardinals to decide that a simple majority of the ballots will be enough to elect a pope.

Years or days

A quick election would signal an easy consensus, while delays would likely indicate multiple candidates with opposing factions of supporters. While conclaves in medieval times lasted as long as three years, the longest in the 20th century - the election of Pope Pius XI in 1922 - took 14 ballots over five days.