VATICAN CITY - With a humble "Grazie" as bishops doffed their miters and applause echoed through St. Peter's Basilica, a frail Pope Benedict XVI began his long farewell by presiding over Ash Wednesday services in a tearful, final public Mass.
"We wouldn't be sincere, Your Holiness, if we didn't tell you that there's a veil of sadness on our hearts this evening," said Cardinal Tarcisio Bertone, Benedict's longtime deputy, his voice breaking.
"Thank you for having given us the luminous example of the simple and humble worker in the vineyard of the Lord," Bertone said, quoting Benedict's own words when he first appeared before the faithful above St. Peter's Square after he was elected pope.
Smiling and clearly moved, Benedict responded, "Grazie. Now let us return to prayer" - his words bringing to an end the resounding applause that had grown in intensity over several minutes.
Then, in a rare gesture and sign of respect, the rows of bishops, some with tears in their eyes, removed their miters. One prelate dabbed at his eyes with a handkerchief.
"Viva il papa!" someone in the crowd shouted as the pope slowly made his way down the steps of the altar, assisted by two clergymen. He then departed St. Peter's for the last time aboard a wheeled platform, sparing him the long walk down the aisle.
Ash Wednesday marks the start of Lent, the most solemn season on the church's liturgical calendar that ends with Holy Week, when the faithful commemorate the death of Christ and his resurrection on Easter Sunday. By this Easter, on March 31, the church will likely have a new pope.
In his final homily as pontiff, Benedict sent a clear message to his successor and those who will elect him of his hope for the future: a united church that isn't "defiled" by internal rivalries.
Each Christian, he said, is called to bear witness to the faith. "I think in particular of the attacks against the unity of the church, to the divisions in the ecclesial body," he said.
"Experiencing Lent in a more intense and evident ecclesial union, moving beyond individualisms and rivalries, is a humble and precious sign for those who have drifted from the faith or are indifferent to it."
Earlier in the day, the scene was festive as Benedict took the extraordinary step of speaking directly to the faithful about why he had broken with 600 years of tradition and decided to retire on Feb. 28.
"As you know, I have decided to renounce the ministry that the Lord gave to me on April 19, 2005," Benedict told thousands gathered for the traditional Wednesday general audience. "I did this in full liberty for the good of the church."
He expressed gratitude for the prayers and love of his flock, which he said he "physically felt in these days that haven't been easy for me." And he asked them to "continue to pray for me, the church and the future pope."
Benedict was greeted with a standing ovation when he entered the packed hall, and his speech was interrupted repeatedly by applause.
A huge banner reading "Grazie Santita" - "Thank you Your Holiness" - was strung up, and a chorus of Italian schoolchildren serenaded him with one of his favorite hymns in German - a gesture that moved the pope to thank them for singing a piece "particularly dear to me."
He appeared wan and spoke softly, but his eyes twinkled at the welcome.