Pope Benedict XVI decried what he called the mistaken idea that leading a virtuous life was "boring" as he marked Thursday's 40th anniversary of the end of Vatican Council II, which sparked modernizing reforms in the 2,000-year-old Roman Catholic Church.

Among those who were eager participants at the 1962-1965 council but who later questioned whether its legacy was too loosely interpreted by liberal clergy was a young German theologian, Joseph Ratzinger, now Pope Benedict.

He praised his predecessors in the papacy for guiding the Church "on the route of authentic council (inspired) renewal, working ceaselessly for the faithful interpretation and implementation" of the council.

During a solemn anniversary ceremony in St. Peter's Basilica, Benedict used his homily to talk about use of freedom and its relationship with evil.

"Man nurtures the suspicion that God, at the end of the day, takes something away from his life, that God is a competitor who limits our freedom and that we will be fully human only when we will have set him aside," Benedict said.

"There emerges in us the suspicion that the person who doesn't sin at all is basically a boring person, that something is lacking in his life, the dramatic dimension of being autonomous, that the freedom to say 'no' belongs to real human beings," the pontiff said.

In remarks after Mass, Benedict urged people to "overcome the temptation of a mediocre life, made of compromises with evil."

Vatican Council II, with its call for modernization, was a turning point for the church. The council's reforms allowed Mass to be celebrated in languages other than Latin, folk songs and guitar-playing were permitted, and priests at the altar faced congregations instead of having their back to them.

The council called for efforts to bridge differences between Catholics and other Christians. It also produced a document in which the Catholic Church deplored anti-Semitism and repudiated the "deicide" charge that blamed Jews as a people for Christ's death.

Among those in the packed basilica was a Methodist delegation.

Some churchmen felt the council's reforms went too far, especially when embraced by theologians espousing Liberation Theology, which blended the Gospel with Marxist-influenced politics, particularly in Latin America.

Under John Paul II, Ratzinger became the Vatican's guardian of doctrinal orthodoxy and cracked down on Liberation Theology as well as on theologians and clergy deemed to have been too liberal in interpreting the Council's legacy.

The abrupt changes, with emphasis on modernization and a sense of freedom, delighted some clergy and disoriented others. Many priests and nuns abandoned religious life in the United States and other affluent countries.

John XXIII, who convened Vatican Council II, died in 1963. The meeting was brought to its conclusion by his successor, Paul VI.

When Benedict appeared at his window overlooking St. Peter's Square, he blessed the Olympic torch, which was making its way to Turin, the site of the Winter Games in February, and said the Olympics were based on peace and brotherhood.