STORY: Bells rang out across St Peter's Square on Saturday (December 31) as the death of former Pope Benedict XVI was announced.
A spokesperson for the Holy See said the 95-year-old had passed away at the Vatican's Mater Ecclesiae Monastery on Saturday morning.
He had been living there since 2013, when he became the first pontiff in 600 years to resign.
Earlier this week Pope Francis had disclosed during his weekly general audience that his predecessor was "very sick" and asked for people to pray for him.
Benedict, who in 2005 became the first German pope in 1,000 years, had good relations with his successor.
However, his continued presence inside the Vatican ideologically polarized the Church.
Conservatives alarmed by Francis's progressive moves had looked to Benedict as a guardian of tradition.
The Vatican said that Benedict's body will lie in state from Monday (January 2) in St. Peter's Basilica.
The Vatican has painstakingly elaborate rituals for what happens after a reigning pope dies, but no publicly known ones for a former pontiff.