The world's faithful prayed for the soul of the late Pope Benedict XVI this morning as his body laid in state inside the Vatican monastery.
During his Sunday service today, Pope Francis prayed for his predecessor's soul and its passage to heaven, again expressing thanks for his lifetime of service to the Church.
Benedict - the first Pontiff to resign in 600 years - was 95-year-old when he died in the early hours of Saturday morning in his retirement quarters - where he'd lived since stepping down in 2013 due to his ailing health.
St Peter's Basilica, where Francis presided over today's mid-morning New Year's Mass, is set to host Benedict's coffin starting from tomorrow.
During the service, Francis called Benedict a "noble, kind" and "gifted [sic] to the Roman Catholic Church".
US President Joe Biden and President Lula of Brazil were among dozens of leaders to praise the former pontiff.
Thousands of the faithful are expected to visit the coffin during three days of viewings.
Today, Benedict's body - dressed in a mitre, a bishop's headgear, and a red cloak-like vestment - laid on a burgandy-coloured bier in the chapel of the Vatican monastery.
A rosary was wrapped between his hands, which were clasped together above his waist in prayer.
Behind his body stood the chapel's altar and a Christmas tree covered in decorations.
Francis looked weary and sat with his head bowed as Mass began on the first day of the year, an occasion the Catholic church dedicates to the theme of peace.
He departed briefly from reading his homily, with its emphasis on hope and peace, to pray aloud for Benedict.
"Today we entrust to our Blessed Mother our beloved Pope Emeritus Benedict XVI, so that she may accompany him in his passage from this world to God," he said.
Later, Francis delivered more remarks about the retired pontiff when he offered New Year's greetings to thousands gathered in St. Peter's Square
Referring to Mary, Francis said that "in these hours, we invoke her intercession, in particular for Pope Emeritus Benedict XVI, who, yesterday morning, left this world."
"Let us unite all together, with one heart and one soul, in giving thanks to God for the gift of this faithful servant of the Gospel and of the church," said Francis, speaking from a window of the Apostolic Palace to pilgrims and tourists below.
The square will be the setting for Benedict's funeral led by Francis on Thursday morning. That rite will be a simple one, the Vatican has said, in keeping with the wishes of Benedict, who for decades as a German cardinal had served as the Church's guardian of doctrinal orthodoxy before he was elected pope in 2005.
In the last years, Francis has hailed Benedict's stunning decision to become the first pope to resign in 600 years and has made clear he'd consider such a step as an option for himself.
Hobbled by knee pain, Francis, 86, on Sunday arrived in the basilica in a wheelchair, before taking his place in a chair for the Mass, which was being celebrated by the Vatican's secretary of state.
Francis, who has repeatedly decried the war in Ukraine and its devastation, recalled those who are victims of war, passing the year-end holidays in darkness, cold and fear.
"At the beginning of this year, we need hope, just as the Earth needs rain," Francis said in his homily.
When addressing the faithful in St. Peter's Square, Francis cited the "intolerable" war in Ukraine, which began in February of last year with Russia's attacks and invasion, and in other places in the world.
Yet, Francis said, "let us not lose hope" that peace will prevail. "In the entire world, in all peoples, a cry is rising, `no to war, no to re-armament' but (may) the resources go to development, health, food, education, work."