Vatican City - Today is Inauguration Day for the Catholic Church's 266th leader.
Pope Francis' installation ceremony is underway at the Vatican this morning.
Thousands of well wishers poured into St. Peter's Square to see the new pope.
The installation mass is much simpler than the 2005 ceremony for Pope Benedict XVI.
Blue and white flags from Pope Francis's native Argentina lined the square.
The ceremony drew 132 official delegations and religious leaders from around the world - including the leader of the world's Orthodox Christians who is attending for the first time since the two branches of Christianity split 1,000 years ago.