The 83-year-old John Paul planned to preside over an anniversary Mass in St. Peter's Square starting at 6 p.m. (Noon EDT) — about the same time that white smoke from a Vatican chimney alerted the world a quarter-century ago that a Polish cardinal named Karol Wojtyla had been elected the first non-Italian pope in 455 years.
Cardinals from around the world have gathered in Rome for the festivities and the Mass, which was expected to draw tens of thousands of pilgrims to St. Peter's Square, including representatives from the 301 Roman parishes John Paul has visited, and be watched by millions more on television.
CBS News Early Show Co-Anchor Harry Smith, in Rome for the anniversary, reports that the pontiff, in a meeting with cardinals and bishops, stressed how important their role as pastor is to their flocks and urged them to get to know each one of the members, even those that have lost their way.
The Vatican was marking the anniversary with great celebration, but there was also a very bittersweet atmosphere in Rome since the pope, who suffers from Parkinson's disease, is so clearly ailing.
"He's frail, obviously, and been frail for a while. He's hurting," said Cardinal Theodore McCarrick, archbishop of Washington, D.C.
Nevertheless, John Paul has continued to defy skeptics by pressing on, insisting on keeping up with his taxing schedule despite his inability to walk or even stand. He continues to hold public audiences despite his increasing difficulty speaking and making clear he has no plans to step down.
Thursday's activities called for John Paul to sign an exhortation on the role of bishops and to give a speech to cardinals, followed by the evening Mass to celebrate his election by the College of Cardinals who had gathered 25 years ago to name a successor to Pope John Paul I, who died after only 34 days in the papacy.
On that day the first plumes of white smoke began pouring out of the Sistine Chapel chimney at 6:18 p.m., the sign that the cardinals had found their next pope. At 6:45 p.m., Cardinal Pericle Felici announced the news from the balcony of St. Peter's Basilica, and at 7:15 John Paul II made his first appearance to the world, asking for patience from Italians because he didn't speak their language perfectly.
Since that day, John Paul has had a remarkable tour, helping to bring down communism in eastern Europe by sparking what amounted to a peaceful revolution in his Polish homeland; seeking to heal divisions between Christians and Jews; and working tirelessly for peace in the world, most recently in Iraq.
John Paul is the most-traveled pope ever, visiting 129 different countries in 102 foreign trips. He made more saints than any of his predecessors over the past 500 years combined — a total of 476 — part of his aim to give his sometimes flagging flock more role models.
On Sunday, as part of his anniversary celebrations, he will beatify Mother Teresa, the nun who devoted most of her life to caring for the sick and destitute.
John Paul also ushered the Vatican into the media age, becoming something of a media superstar and drawing cheering crowds wherever he went, particularly among the young. Over the course of his pontificate, more than 16.7 million people by Vatican statistics attended his weekly Wednesday general audiences alone.
"With his presence in the media and his world travels, he is truly the global pope," said Cardinal Christoph Schoenborn, the archbishop of Vienna, Austria and a man mentioned as a possible successor to John Paul.
On church doctrine, John Paul has toed a conservative line, particularly in matters concerning what he called the sanctity of human life: abortion, contraception and euthanasia are all banned in the church under John Paul. He ruled out letting priests marry or allowing women to be ordained, and recently endorsed a worldwide campaign to keep same-sex unions from receiving legal recognition.
Such hard-line positions alienated some Catholics and sparked criticism that the Vatican was out of touch with 21st century society. In particular, the church's opposition to condoms has been blamed by some for hurting the fight against AIDS.
For all the controversy and for all his successes, John Paul also had his disappointments: the church sex scandal in the United States weighed heavily on him, and he has never realized his dream of visiting Russia. The Russian Orthodox Church accuses the Vatican of poaching on traditionally Orthodox lands — a charge the Vatican denies.
But John Paul still hasn't ruled out a trip to Moscow, and his spokesman, Joaquin Navarro-Valls says the pope may accept invitations for visits next year to Austria, Switzerland and France as well as a return to his homeland.
And he has one more milestone looming: He will become the third longest-serving pope if he surpasses Pope Leo XIII's reign of 25 years and four months about a century ago. The first pope, St. Peter, served as leader of the church for at least 34 years and is considered the longest-serving pontiff.