Pope Benedict XVI celebrated a memorial mass for his predecessor, John Paul II, to mark the first anniversary of his death. Thousands of pilgrims from all over the world filled Saint Peter's Square to attend the ceremony.

For the past two days, tens of thousands of people have crowded Saint Peter's Square to pay tribute to Pope John Paul II, who died April 2 of last year. After an evening vigil Sunday night, Pope Benedict XVI, Monday, celebrated a solemn mass.

Cardinals, bishops, priests as well as tens of thousands of pilgrims from all over the world, many from John Paul's native Poland, attended the open-air mass. Cardinal Stanislaw Dziwisz, the late pope's longtime private secretary, was also present.

Pope Benedict appeared wearing red vestments. He blessed the crowd as he made his way up the steps of Saint Peter's Basilica.

In his homily, Benedict said that during these days the memory of John Paul II is particularly present in the Church and in the world. Speaking of his many human and spiritual gifts, he called John Paul a "rock" in the faith.

He said those who were able to know him were able to experience his sincere and solid faith that, while impressing his collaborators, also spread its beneficial influence during his entire pontificate, to the whole Church, in a crescendo, which reached its culmination during the last months and days of his life.

Pope Benedict said John Paul's was a convinced, strong and authentic faith, free from fears and compromises that were contagious for the heart of many people, thanks to his many apostolic pilgrimages to every part of the world, and especially thanks to that last "trip" which was his agony and death.

Benedict said that this evening, thoughts return with emotion to the moment of death of the beloved pope, but at the same time the heart is as if pushed to look forward. We hear, Benedict added, his many invitations to move ahead without fear on the road of faith in the Gospel to be heralds and witnesses of Christ in the third millennium.

"We are reminded," Pope Benedict added, "of his endless calls to cooperate generously in the realization of a more just and supportive humanity, to be workers of peace and builders of hope"

At an evening prayer vigil Sunday, which marked the exact time of John Paul's death, Pope Benedict said his predecessor continues to live in our minds and in our hearts. In May last year, soon after his election, Pope Benedict put his predecessor on the fast-track to sainthood.