Pope Benedict XVI has died at the age of 95, almost a decade after he resigned from his position as head of the Catholic Church due to advanced age.
He led the Catholic Church for less than eight years until, in 2013, he became the first pope to resign since Gregory XII in 1415.
Benedict spent his last years in the Mater Ecclesiae monastery within the walls of the Vatican.
His successor Pope Francis said he had visited him there often.
Although the former Pope had been ill for some time, the Holy See said that his condition was stable, but that there was apparently a rapid deterioration due to age.
On Wednesday, Pope Francis called on his year-end audience at the Vatican to "say a special prayer for Pope Emeritus Benedict", who he said was very ill.
Born Joseph Ratzinger in Germany, Benedict was 78 when he became one of the oldest popes ever elected in 2005.
For most of his papacy, the Catholic Church faced accusations, legal claims and official reports of decades of child abuse by priests.
Earlier this year, the former pope admitted that mistakes had been made in the handling of abuse cases when he was archbishop of Munich between 1977 and 1982.