Many pilgrims from Poland, the late pontiff's homeland, joined Benedict in prayer Monday evening.
The 84-year-old John Paul died on April 2, 2005, after battling Parkinson's disease. The commemoration was held a few days earlier because April 2 this year falls on Good Friday, when Benedict will preside over Lenten services at the Vatican and at the Colosseum in Rome.
Immediately after John Paul's death, faithful were clamoring for his sainthood. But this anniversary comes amid some doubts that a miracle needed for his saint-making will stand up to scrutiny. And there have been questions about John Paul's record in combatting pedophile priests.
