Former Pope Benedict, who in 2013 became the first pontiff in 600 years to resign, died on Saturday aged 95 in a secluded monastery in the Vatican where he had lived since stepping down, a spokesman for the Holy See said.
Bells tolled across the tiny Vatican City as news of his death spread to the faithful on an unusually warm, sunny day.
The Vatican said his body would lie in state from Monday in St.Peter's Basilica and his funeral will be held on the morning of Jan. 5. Pope Francis will preside over the ceremony, which will take place in the huge square in front of the basilica.
"With sorrow I inform you that the Pope Emeritus, Benedict XVI, passed away today at 9:34 in the Mater Ecclesiae Monastery in the Vatican," spokesman Matteo Bruni said in a statement.
Earlier this week, Pope Francis disclosed that his predecessor was "very sick". Bruni said he had received his last rites, called "the anointing of the sick", on Wednesday.
Leaders were swift in sending their condolences for Benedict, who was the first German pope in 1,000 years.
"A Christian, a pastor, a theologian: (he was) a great man who history will not forget," said Italian Prime Minister Giorgia Meloni.
French President Emmanuel Macron said Benedict "worked with all his soul and intelligence for a more fraternal world", while Markus Soeder, the state premier of his native Bavaria in Germany, hailed him as "one of the most influential theologians of the 20th century".
For nearly 25 years, as Cardinal Joseph Ratzinger, Benedict was the powerful head of the Vatican's doctrinal office, then known as the Congregation for the Doctrine of the Faith (CDF).
He was elected pope on April 19, 2005 to succeed the widely popular Pope John Paul II, who reigned for 27 years. Cardinals chose him from among their number seeking continuity and what one called "a safe pair of hands".
Child abuse scandals hounded most of his papacy but he is credited with jump-starting the process to discipline or defrock predator priests after a more lax attitude under his predecessor.
But Benedict himself acknowledged that he was a weak administrator, saying he showed a "lack of resolve in governing and decision taking," during his eight-year papacy which was marked by missteps and a leaks scandal.
After his resignation, which shocked many in the Church, Catholic conservatives looked to the former pope as their standard bearer and some ultra-traditionalists even refused to acknowledge Francis as a legitimate pontiff.
They have criticised Francis for his more welcoming approach to members of the LGBTQ+ community and to Catholics who divorced and remarried outside the Church, saying both were undermining traditional values.
Francis himself said having Benedict at the Vatican was like a "grandfather living in the house" and would regularly visit his predecessor.