VATICAN CITY (RNS) Pope Benedict XVI on Thursday (Oct. 11) urged Catholics to confront the spiritual “desert” of today's secularized world and to rediscover “the truth and beauty of the faith.”

Benedict celebrated a solemn Mass in St. Peter's Square to mark the 50th anniversary of the Second Vatican Council, a worldwide gathering of Catholic bishops that revolutionized the church's stance toward the modern world and to other religions.

Thursday's celebration inaugurated the Year of Faith, a yearlong series of events in dioceses and parishes aimed at reinvigorating Christian belief against a mounting tide of secularism.

“Recent decades have seen the advance of a spiritual 'desertification,'” Benedict said. “We see it every day around us. This void has spread.”

Reviving the dwindling influence of the church's message in society has been a main concern for the 85-year old pontiff.

On Sunday, Benedict inaugurated a three-week gathering of bishops to focus on the “new evangelization,” aimed at developing a strategy for a church confronted by the rapid decline of faith in regions that until recently were its strongholds, such as Europe and Latin America.

For many, the roots of today's crisis date back to Vatican II (1962-1965) and to the dramatic changes, inside and outside the church, of the following decades.

Benedict, who took part in the council as a young theologian, has often seemed to agree with those critics.

On Thursday, he said the council opened up to “dialogue with the modern world” only because its faith was rock solid, but that in the following years, “many embraced uncritically the dominant mentality” and doubted the “very foundations” of Catholic faith.

He urged Catholics to avoid the “extremes of anachronistic nostalgia and running too far ahead.”

KRE/AMB END SPECIALE