Crowds flood St. Peter's for Pope's inaugural Mass

VATICAN CITY, Sunday (Reuters) Pilgrims and priests, presidents and patriarchs flowed into St. Peter's Square on Sunday for the inaugural Mass of Pope Benedict, three weeks after the death of his predecessor John Paul.

Up to half a million people were expected to pack the square and surrounding streets to see the 78-year-old Pontiff receive the symbols of his new office and hear his first public sermon as leader of the 1.1 billion-member Roman Catholic Church.

As the sun rose over Rome, a steady stream of faithful poured through the roads leading to St. Peter's, many of them the Pope's compatriots waving German and Bavarian flags.

Security was again tight for the last main event in the papal transition, as it was for the funeral mass for John Paul.

Rome shut its airspace ahead of the open-air service, blocked off roads and had anti-aircraft missiles and a NATO plane guarding against attack.

Nuns in black habits rushed to grab good vantage points in the cobbled square, clerics' cloaks billowed in the light spring breeze and convoys of official delegations from more than 100 countries swept through Rome with police sirens wailing.

"It was sad to lose John Paul but it is beautiful to be here to welcome Benedict," said Carla Moccia, an Italian student.

The shy Pope, who as Cardinal Joseph Ratzinger was John Paul's top doctrinal overseer, has been slowly growing more comfortable in his new role since being elected in a secret conclave as the Church's 265th pontiff last Tuesday. He was expected to drive around the vast St. Peter's Square after the Mass in an open-topped car to greet the faithful, giving him an early taste of the sort of crowds that are likely to follow him throughout his papacy.

Fewer world leaders were due at the Mass than at John Paul's funeral, which with 2,500 dignitaries resembled a summit of the world's powerful, but the attendance list was still long.

Chancellor Gerhard Schroeder and President Horst Koehler were heading the German delegation. The U.S. group is led by Florida Gov. Jeb Bush, brother of U.S. President George W. Bush and a convert to Roman Catholicism.

The guest list included Spain's King Juan Carlos and Archbishop of Canterbury Rowan Williams, the spiritual head of the Anglican Communion.

Also present will be Benedict's brother Georg, 81 and also a priest. The two-hour Mass will be in Latin with prayers in languages from German to Arabic and Chinese.