Thousands of mourners are expected to pay their respects to former Pope Benedict XVI when his lying in state begins at the Vatican on Monday.
The former pontiff died on New Year’s Eve at the age of 95.
He led the Catholic Church for eight years before, in 2013, becoming the first pope in 600 years to resign.
His remains will lie in state for three days.
Benedict's successor Pope Francis will lead the funeral in St Peter's Square on Thursday, before he is laid to rest in the tombs beneath St Peter's Basilica.
He died at the Mater Ecclesiae monastery inside the Vatican gardens, which had been his home for the past decade.
The Vatican on Sunday released images of Benedict lying in state in the monastery chapel, dressed in red papal mourning robes and with a gold-edged mitre.
He shocked the world on February 11, 2013, when he announced in Latin that he was resigning, telling cardinals he was too old and frail to lead an institution with more than 1.3 billion members.
“There were moments of joy and light, but also moments that were not easy … There were moments … when the seas were rough and the wind blew against us and it seemed that the Lord was sleeping,” Benedict told his last general audience, a gathering of more than 150,000 people.
His resignation created the extraordinary situation of having two “men in white” — Francis and Benedict — at the Vatican.
Benedict's funeral will also break new ground.
Papal deaths usually trigger the calling of a conclave of cardinals to elect a successor, but this time Francis remains in post, and will lead proceedings.
Pope Benedict XVI - in pictures
Benedict's funeral will be “solemn but simple”, the Vatican said.
It has yet to say who will be attending, beyond that it will include delegations from Italy and Benedict's native Germany.
The last papal funeral, of John Paul II in 2005, drew one million faithful and heads of state from around the world, although Benedict was a more divisive figure.
A brilliant theologian, he alienated many Catholics with his staunch defence of traditional values and as pope struggled to impose his authority on the church as it battled a string of crises, including over clerical sex abuse.
Benedict repeatedly apologised for the Church's failure to root out sexual abuse of children by clergy and he was the first pope to take serious action against abuse.
But in 2022, an independent report in Germany claimed that Benedict had failed to take action in four abuse cases when he was Archbishop of Munich, between 1977 and1982.
He acknowledged in an emotional personal letter that errors had occurred and asked for forgiveness. His lawyers argued that he was not directly to blame.
After the election of Pope Francis, Benedict moved to spend his final years in prayer, reading, playing the piano and receiving friends.
Although he said he would remain “hidden from the world”, Benedict sometimes caused controversy through his writings.
In an essay for a Church magazine in Germany in 2019, he blamed the crisis over the abuse of children by priests on the effect of the 1960s sexual revolution, what he called homosexual cliques in seminaries and a general collapse in morality.
Critics accused him of trying to shift the blame away from the Church hierarchy.
Pope Francis, an Argentine Jesuit who is most at home among his flock, paid tribute to Benedict in three New Year's events at the Vatican at the weekend, “thanking God for the gift of this faithful servant of the Gospel and of the Church”.
Francis, 86, has raised the prospect that he might follow Benedict's example and step down if he became unable to carry out his duties.
In July, suffering knee problems that have forced him to rely on a wheelchair, he admitted he needed to slow down or think about stepping aside.
Last month, Francis revealed he had signed a resignation letter when he took office should poor health prevent him from carrying out his duties.