Around the world, millions more watched the funeral service on television.
"The funeral Mass was what most Roman Catholics experience whenever they lose someone," said CBS News Analyst Father Paul Robichaud. "What was so powerful was that the entire world was at the funeral."
Applause rang out in the wind-whipped square as the funeral began with John Paul's plain cypress coffin, adorned with a cross and an "M" for the Virgin Mary, was brought out from St. Peter's Basilica and placed on a carpet in front of the altar. The book of the Gospel was placed on the coffin and the wind lifted the pages.
After the Mass ended, bells tolled and 12 pallbearers with white gloves, white ties and tails presented the coffin to the crowd one last time, and then carried it on their shoulders back inside the basilica for burial — again to sustained applause from the hundreds of thousands in the square, including dignitaries from 138 countries.
The first non-Italian pope in 455 years was buried at 2:20 p.m. (8:20 a.m. EDT) in the grotto under the basilica, attended by prelates and members of the papal household, the Vatican said.
Nearly 4 million people jammed into Rome since the pope died Saturday, doubling the city's population. There has been no major violence despite the crowds and the many dignitaries, including heads of state, although an apparent miscommunication after the funeral prompted Italian air force jets to intercept a plane flying in to pick up an official delegation.
The 2½-hour Mass began with the Vatican's Sistine Choir singing the Gregorian chant, "Grant Him Eternal Rest, O Lord."
Cardinal Joseph Ratzinger, dean of the College of Cardinals, a close confidant of John Paul and a possible successor, presided at the Mass and referred to him as our "late beloved pope" in a homily that traced the pontiff's life from his days as a factory worker in Nazi-occupied Poland to his final days as the head of the world's 1 billion Catholics.
Interrupted by applause at least 10 times, the usually unflappable German-born Ratzinger choked up as he recalled one of John Paul's last public appearances — when he blessed the faithful from his studio window on Easter.
"We can be sure that our beloved pope is standing today at the window of the father's house, that he sees us and blesses us," he said to applause, even among the prelates, as he pointed up to the third-floor window above the square.
"Today we bury his remains in the earth as a seed of immortality — our hearts are full of sadness, yet at the same time of joyful hope and profound gratitude," Ratzinger said in heavily accented Italian.
He said John Paul was a "priest to the last" and said he had offered his life for God and his flock "especially amid the sufferings of his final months."
"It was a wonderful juxtaposition between the young Karol Wojtyla and the old, suffering pope in the last years of his life, which Cardinal Ratzinger beautifully paralleled," Robichaud added.
Ratzinger was interrupted again toward the end of the Mass by several minutes of cheers, rhythmic applause and shouts of "Giovanni Paolo Santo" or "Saint John Paul," from the crowd.
"We saw this ancient ritual, these very, very beautiful ancient prayers in Latin and in Greek. Yet at the same time, it was punctuated constantly by the uproar of the crowd," observed Robichaud.
John Paul requested in his to be interred "in the bare earth," and he was laid to rest among the pontiffs from centuries past near the tomb traditionally believed to be of the apostle Peter, the first pope.
The coffin was definitively closed with red bands and both papal and Vatican seals, and nested inside a second casket of zinc and then within a third of walnut. The outside casket bears the name of the pope, his cross and his papal coat of arms.