Pope Benedict XVI took charge of his Church at a majestic inauguration and set down a spiritual manifesto for his papacy with a plea for humanity to escape "a desert of suffering and embrace God".
Three weeks after the death of John Paul, presidents and pilgrims again packed the cobbled expanse in front of St Peter's Basilica to see the new pontiff installed on the papal throne as the leader of 1.1 billion Roman Catholics.
Cloaked in shimmering golden vestments, Pope Benedict told a 350,000-strong crowd that he was "a weak servant of God" and appealed for prayers to help him in the "enormous task that truly exceeds human capacity".
He again promised to continue John Paul's policy of reaching out to Jews and other faiths, and pays his first visit outside the Vatican on Monday to St Paul Outside the Walls, a Rome basilica with a special place in the quest for Christian unity.
The thrust of the pontiff's homily, however, was a call for the world to rediscover its spirituality and a plea for support in a task he said "truly exceeds all human capacity".
Applause echoed around the colonnaded square as flag-waving pilgrims interrupted his powerful sermon more than 40 times, chanting "Benedict, Benedict," at the end of the speech.
Pilgrims chanted his name at the
end of the ceremony
The pontiff, formerly Cardinal Joseph Ratzinger, was the austere guardian of Catholic orthodoxy under John Paul, but on Sunday he looked to soften his image and deflect concerns over his past as a tough doctrinal enforcer.
"My real programme of governance is not to do my own will, not to pursue my own ideas, but to listen, together with the whole Church, to the word and the will of the Lord," the 78-year-old German said to loud applause.
At the end of the 2-1/2 hour Mass, the pope was driven around the square in a white, open-topped vehicle, smiling and waving as he passed through a sea of cheering pilgrims.
"I liked his homily a lot. He took up the previous pope's words. This should be a papacy of continuity," Silvio Viccierhai, a 50-year old Italian, said.
Benedict called for Catholics to
Security was again tight, as it was for the funeral for John Paul. Rome shut its airspace, closed roads and had anti-aircraft missiles and a Nato plane guarding against attack.
Benedict, the oldest man to be elected pope for three centuries, takes over the Church at a time of dwindling congregations and an ageing base in Europe and stiff competition from evangelical sects for followers in the developing world.
In his first sermon as the 265th leader of the Church, delivered entirely in Italian, he focused on what he called a world of alienation, suffering and death that he said had become a spiritual wasteland.
Facing such woes, he said, his Church was still very much alive, young and able to grow.
"There are so many kinds of desert. There is the desert of poverty, the desert of hunger and thirst, the desert of abandonment, of loneliness, of destroyed love," the pope said.
"Pray for me, that I may learn to love the Lord more and more"
"There is the desert of God's darkness, the emptiness of souls no longer aware of their dignity or the goal of human life. The external deserts in the world are growing, because the
internal deserts have become so vast.
The pope was elected in a secret conclave of the Church's 115 voting cardinals after just three rounds of voting last Tuesday. He is the 16th pontiff to take the name Benedict.
"My dear friends - at this moment I can only say: Pray for me, that I may learn to love the Lord more and more," he said.
"Pray for me, that I may not flee for fear of the wolves."
Many in the square and surrounding streets, where crowds followed the Mass on large television screens, were the pope's compatriots waving German and Bavarian flags.
Fewer world leaders were at Sunday's Mass than at John Paul's funeral, which, with 2500 dignitaries, resembled a summit of the world's powerful. But the attendance list was still long, with about 140 official delegations present.
Chancellor Gerhard Schroeder and President Horst Koehler headed the German delegation. The US group was led by Florida Governor Jeb Bush, brother of US President George Bush and a convert to Roman Catholicism.