Vatican officials said around 50,000 tickets had been requested for the occasion, which is likely to draw many more pilgrims into the broad boulevard leading toward the Vatican from the River Tiber.
The pope sent shock waves around the Roman Catholic world on Feb. 11 when he announced he would resign on Thursday — the first pope to have done so voluntarily in six centuries.
The announcement left officials scrambling to deal with the protocols of his departure as he ceases to be the leader of the world's 1.1 billion Roman Catholics. Only on Tuesday did the Vatican announce that he will keep the name Benedict XVI and will be known as the Roman pontiff emeritus or pope emeritus.
He will dress in a simple white cassock, forgoing the mozzetta, the elbow-length cape worn by some Catholic clergymen, the Vatican spokesman, the Rev. Federico Lombardi, told reporters at a news briefing on Tuesday.
And he will no longer wear the red shoes typically worn by popes, symbolizing the blood of the martyrs, Father Lombardi said, opting instead for a more quotidian brown.
Benedict's looming departure has also triggered a surge of maneuvering among the 117 cardinals who will elect his successor in a conclave starting next month, reviving concerns about the clerical abuse scandals that dogged Benedict's time at the Vatican.
Indeed, the abrupt resignation of the most senior Roman Catholic cardinal in Britain on Monday — after accusations that he made unwanted sexual advances toward priests years ago — showed that the taint of scandal could force a cardinal from participating in the selection of a new pope.
His exit came as at least a dozen other cardinals tarnished with accusations that they had failed to remove priests accused of sexually abusing minors were among those gathering in Rome to prepare for the conclave.
But there was no indication that the church's promise to confront the sexual abuse scandal had led to direct pressure on those cardinals to exempt themselves from the conclave.
Rachel Donadio reported from Rome, and Alan Cowell from Paris.
