Pope Benedict XVI on Sunday opened a meeting of Roman Catholic Church leaders from around the world to debate how to counter rising secularism on the 50th anniversary of the momentous Second Vatican Council.
The synod of 262 archbishops, bishops and other senior clerics heard a call from the pope for a "new evangelism" for the Catholic Church, which is fast losing followers in Europe and feels increasingly discriminated against in many parts of the world.
The three-week synod coincides with the announcement on October 11 of a "Year of Faith" to mark the anniversary of the start of the Second Vatican Council (1962-1965), which changed the face of Catholicism.
In Saint Peter's Square on Sunday, Benedict said the Council had been "the most universal expression" of the spiritual dynamic of the 20th century.
Pope Benedict XVI leads the mass of the opening of the synod of bishops on October 7 in St Peter's Square in the Vatican. The synod is to debate how to counter rising secularism on the 50th anniversary of the momentous Second Vatican Council.
He shunned any reference to the latest scandal to rock the 2,000-year-old institution, the trial of his butler Paolo Gabriele who was convicted on Saturday of stealing secret papers from the papal palace.
The 85-year-old head of the Roman Catholic Church, who was an expert at the Council known as "Vatican II" and one of its most reformist voices, has made the new evangelism a centrepiece of his papacy since being elected in 2005.
At the start of the synod a tired-looking, pale Benedict stressed that marriage and family must be at the centre of the new evangelism, as there was "an obvious link between the crisis of the faith and the crisis of marriage".
The meeting will also look at the discrimination of Christians in parts of the world including on the part of radical Islamists, as well as increasing competition from evangelical churches, particularly in the developing world.
The last synod on evangelism was called by Paul VI in 1974 but the crisis of faith in traditionally Christian countries was not as strong then.
Bishops attends a mass celebrated by Pope Benedict XVI for the opening of the Synod of bishops on October 7 in St Peter's Square in the Vatican. The meeting will look at the discrimination of Christians in parts of the world including on the part of radical Islamists, as well as increasing competition from evangelical churches, particularly in the developing world.
The Vatican earlier this year revealed the answers given by bishops to a questionnaire asking them to identify obstacles in spreading the Gospel.
Some talked about the problem of "excessive bureaucracy in Church structures", others said "liturgical celebrations were devoid of deep spiritual experience" or that the problem was "an insufficient number of clergy".
A 35-year-old German priest at the time of Vatican II, the then Joseph Ratzinger became more conservative after witnessing the perceived excesses of the 1960s and now aims to correct interpretations of the Council that he sees as deeply erroneous.
Ratzinger in those years was a theologian bursting with new ideas who took an active part in discussions on the possibility of allowing divorcees who re-marry a place in the Catholic Church and even allowing priests to marry.
Pope Benedict XVI leaves after celebrating mass at the opening of the Synod of bishops on October 7 at St Peter's Square in the Vatican. The three-week synod coincides with the announcement on October 11 of a "Year of Faith" to mark the anniversary of the start of the Second Vatican Council (1962-1965), which changed the face of Catholicism.
He was committed to allowing masses to be celebrated in the vernacular instead of Latin and criticised the Vatican for being stuck in the past.
But then came 1968 -- a traumatic year for Ratzinger when students at his faculty interrupted professors and mocked dogma in the name of revolution.
When he was called by the late pope John Paul II in 1981 to lead the Congregation for the Doctrine of the Faith, the main enforcer of Church dogma, Ratzinger started to crack down on left-leaning theologians and priests.
Since being elected pope, he has called for evangelism through an increase in prayer communities and a bigger spotlight to be put on women in the context of their families and parishes as crucial protagonists.
But Vatican expert Marco Politi said: "Vatican II is still the only foundation on which the Church can base its relations with modern society."
Progressive clerical circles share this view and blame the Vatican for taking the Church backward by refusing to adapt to the times.
On Sunday Benedict named two new "doctors of the Church", Spain's 16th-century Saint John of Avila, a priest and religious mystic, and Germany's 12th-century Hildegard of Bingen who did not hesitate to criticise the Church and society of their times.
The title recognizes their holders' importance in contributing to theology or doctrine.