The body of Pope John Paul II has been taken to the Vatican's Apostolic Palace where it is lying in state.
Italy is to hold three days of mourning for the Pope
The Italian Prime Minister Silvio Berlusconi and other mourners have already filed past the body.
On Monday the body will be taken to St Peter's Basilica where as many as a million people are expected to visit to pay their respects to the Pope.
Earlier tens of thousands of people packed St Peter's Square for an open-air Mass in memory of the Pope.
John Paul II died on Saturday after a long illness, aged 84.
On Sunday, the Vatican issued the Pope's death certificate, saying he died from septic shock and irreversible heart failure.
He was Pope for 26 years - the third longest ever - and was the first non-Italian Pope for 455 years.
A date for his funeral has not been set yet, although it is not expected to happen before Wednesday.
Pope John Paul II died on Saturday 2 April 2005
When the Pope's death was announced on Saturday evening the crowds in St Peter's Square gave a huge round of applause - which is an Italian sign of respect - before several minutes of silence.
In Poland, where the Pope was born 84 years ago, some people fell to their knees and wept when the news reached them.
British Prime Minister Tony Blair said John Paul "never wavered, never flinched, in the struggle for what he thought was good and right."
U.S. President George Bush said: "the world has lost a champion of human freedom, and a good and faithful servant of God has been called home."