VATICAN CITY (Reuters) - Pope Benedict launched a campaign to bring lapsed believers back to the Roman Catholic fold on Sunday, opening a major convention of bishops on what the Vatican has termed the "new evangelisation" of the developed world.
The Church is battling losses to its practicing flock in former strongholds in Europe, North America and Latin America in the face of sex abuse scandals, increasing secularism, rival faiths and open dissent against Church teachings on homosexuality and its ban on a female priesthood.
The synod - a Church conference where hundreds of bishops meet to work out a common global strategy, iron out divisions and advise the pope - has the theme "the new evangelisation", the Vatican's buzzword for its drive to woo back believers,
In an open air Mass in St Peter's Square, Benedict defined the campaign as "directed principally to those who, though baptised, have drifted away from the Church and live without reference to Christian life".
The synod's working document spoke of the need to address the divergence between Catholic values and the reality of modern life in Europe and North America, and an "educational emergency" of children no longer being taught the faith.
The Catholic Church, which teaches abstinence outside of heterosexual marriage and opposes divorce, has found itself at variance with some increasingly prevalent societal trends in the developed world.
Pilgrims waved Spanish and Brazilian flags and nuns snapped photographs on camera phones as the pope, dressed in green robes and an ornate white and gold mitre, was driven around the column-lined square, blessing the crowds from his pope mobile.
Sergio Barabaschi, a member of a Milan parish, said the Church's failure to address social change was alienating young people. "The Church is always too slow for the way the times change. Some moral stances are negotiable," he told Reuters.
Enrico Viccardi, an organist from Milan, said it was clear the Church was in difficulty. "Between scandals in the Church and issues like living together outside marriage, it's a very critical time," he told Reuters.
Both said they were influenced by Cardinal Carlo Maria Martini, a former papal candidate considered a leading liberal voice in the Church, who called it "200 years out of date" shortly before he died in August.
At the same ceremony, the pope also named two new "Doctors of the Church", a title given to figures judged to have made a historic contribution to the faith such as Saint Augustine and Saint Thomas Aquinas, bringing the total number to 35.
Saint Hildegard of Bingen, a 12th century abbess, philosopher and polymath, became the fourth woman to hold the title. She and the Spanish clerical reformer Saint John of Avila were the first new Doctors of the Church to be named in 15 years.
The Synod of Bishops has taken place every few years since the 1962-1965 Second Vatican Council, where it was conceived as a way for the papacy to collaborate with its dioceses worldwide and decide common policy and opinion.
This year's conference marks the 50th anniversary of the landmark Council, which attempted to bring the Church up to date with the modern world.
Among its innovations was the introduction of the Mass in local languages after centuries of it being said in Latin.
The Council also encouraged dialogue with other religions and in a landmark document repudiated the concept of collective Jewish guilt for Jesus's death, revolutionising Catholic-Jewish relations after 2,000 years of mistrust.
Reporting by Naomi O'Leary; editing by Philip Pullella