The Polish Embassy to the Holy See said it expected some 10,000 Poles from John Paul's homeland to participate in the Vatican's anniversary commemorations, which also include a Mass on Monday celebrated by Pope Benedict XVI. The city said it was expecting at least 100,000 to 150,000 pilgrims over the weekend.
On Saturday, groups of pilgrims milled about the square, some toting Solidarity flags and banners. John Paul was a firm supporter of Poland's pro-democracy trade union and is credited with helping to overthrow communism in 1989.
Other pilgrims visited John Paul's simple white marble tomb in the grottoes underneath St. Peter's Basilica, kneeling in prayer and tossing flowers and notes onto his grave.
"It is my biggest dream in life to visit his tomb," said Henry Adamczyk, 55, of Lubin, Poland, who said he came to Rome for the anniversary.
"I was happy to hear he died, so he can go and visit his father in heaven," he said while visiting St. Peter's on Saturday.
Pope Beneditct XVI has put his predecessor on the fastest ever track to sainthood, waiving the modern five-year waiting period. He appointed Monsignor Slawomir Oder as the "chief postulator," a kind of holy super lobbyist to promote and defend John Paul's case for sainthood, reports CBS News correspondent Allen Pizzey.
The Chief Postulator told CBS that the new Pope ordered him to do the job "quickly but strictly."
The postulator's office has received more than 5,000 thousand e-mails and letters attesting to the late pope's holiness.
"I receive letters that say, 'Monsignor Oder, don't waste your time. He is a saint already,'" Oder says.
But three miracles must be attributed to John Paul for the process to become inevitable. At least two claims are already being seriously studied, including a nun in France who like John Paul suffered from Parkinson's disease and says she was cured after praying for his intercession, Pizzey reports.
John Paul died April 2 at 9:37 p.m. in his apartment in the Vatican's Apostolic Palace, surrounded by Polish prelates and nuns and his doctors. The cause of death was blood poisoning, as well as kidney and heart failure brought on by a urinary tract infection.
He had suffered for years from Parkinson's disease, and by the end of his life was unable to speak to the faithful, managing only to bless them weakly with his hand.
Sunday's anniversary vigil, to be led by Cardinal Camillo Ruini, is likely to recall the scenes in St. Peter's in the days and weeks before John Paul's death, during which tens of thousands of people lit candles and prayed silently underneath the papal apartment windows.
Ruini, the vicar for Rome, is expected to lead the faithful in recitation of the Rosary prayer, and Benedict is expected to address the crowd near the time of John Paul's death.
On Monday, Benedict celebrates Mass inside the Basilica which is expected to be attended by John Paul's longtime private secretary, the newly elevated Cardinal Stanislaw Dziwisz, archbishop of Krakow.
Edith Degroot, a 37-year-old Dutch businesswoman visiting the Vatican on Saturday, said she was in Rome last year at this time.
"It was impressive, because so many people came to honor him," she said. "I am not Catholic but I enjoy the way they celebrate faith."