VATICAN CITY - The College of Cardinals today set April 18 as the date for the historic start of the conclave to elect a successor to Pope John Paul II, as the Vatican made final arrangements for the funeral expected to draw millions of pilgrims and world leaders to Rome.

The decision came after the cardinals read John Paul's spiritual testament during a pre-conclave meeting today, Vatican spokesman Joaquin Navarro-Valls said, adding that the text would be released Thursday.

Navarro-Valls said cardinals would celebrate a morning Mass on April 18, then be sequestered in the Sistine Chapel in the early afternoon to start the conclave. According to church law, prelates are expected to hold one ballot on the first day of a conclave.

The date was set on the third day of meetings of cardinals who have flocked to Rome for Friday's funeral and burial of John Paul. Navarro-Valls ruled out that the late pope's body might be brought to St. John Lateran basilica, across Rome, before it is buried, as was done for Pope Pius XII when he died in 1958.

The reading of John Paul's testament was unlikely to influence the choice of the 117 cardinals who will cast ballots for the next head of the 1 billion-strong church.

The documents also did not reveal the name of a cardinal John Paul said he named in 2003 but never publicly identified, ending speculation that a last-minute cardinal might join the conclave.

The name of the cardinal was held "in pectore," or "in the heart" - a formula that has been used when a pope wants to appoint a cardinal in a country where the church is oppressed.

Navarro-Valls also said that with huge crowds already converging on Rome, the Vatican could not meet the requests - "by Romans and non-Romans" - for a viewing at what is Rome's cathedral. Instead, John Paul will be buried immediately after the funeral in the grotto under St. Peter's Basilica.

In a major change to a centuries-old practice of electing a new pope, the Vatican has said it planned to ring bells in addition to sending up white smoke to announce that a new pope has been chosen.

Black smoke coming from the chimney of the Sistine Chapel signals no decision has been made after a papal ballot, while white smoke means a pope has been elected.

In the past, it has sometimes been hard to tell whether the smoke from the Vatican chimney was white or black. "This time we plan to ring the bells to make the election of the pope clearer," Archbishop Piero Marini said Tuesday.

In another change from past papal elections, cardinals voting in the conclave will have access to all of Vatican City during the election, as opposed to being sequestered in the Sistine Chapel, Marini said.

Mourners are streaming past John Paul's crimson-robed remains at the rate of 600,000 a day in an almost round-the-clock procession through St. Peter's Basilica, city authorities said. The crush of pilgrims on the road leading to the Vatican will rise sharply when an expected 2 million Poles arrive in Rome for Friday's funeral of the Polish-born pontiff.

Pilgrims stood in a line more than a mile long for 12 hours in chilly pre-dawn temperatures today for a brief glimpse of the pope's body.

Italy was calling in extra police to the capital and planned to seal off much of the Eternal City on Friday to protect a VIP contingent that will include dozens of heads of state from around the world. President Bush and the first lady, former President Clinton, former President Bush and Secretary of State Condoleezza Rice will represent the United States.

John Paul, who died Saturday at 84, made his wish known "to be buried in the ground," said Marini, a longtime aide as papal master of ceremonies.

Marini said John Paul would be buried with a white silk veil on his face, his body clad in liturgical vestments and the white miter. Keeping with tradition, his remains will be placed inside three coffins - wood, zinc and wood - a design meant to slow down the decomposition process.

A small bag of commemorative medals issued over the course of his 26-year pontificate, as well as a sealed document featuring a brief description in Latin of John Paul's life, will be buried with him, Marini said.