Earlier this week, Pope Francis disclosed that his predecessor was "very sick", and asked people to pray for him.
Former pope Benedict XVI, who in 2013 became the first pontiff to resign as head of the Catholic Church since the Middle Ages, has died aged 95, the Vatican announced.
"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," Vatican spokesman Matteo Bruni said in a statement on Saturday.
Earlier this week, Pope Francis disclosed during his weekly general audience that his predecessor was "very sick", and asked people to pray for him.
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).
The former Cardinal Joseph Ratzinger had never wanted to be pope, planning at age 78 to spend his final years writing in the "peace and quiet" of his native Bavaria.
Instead, he was forced to follow the footsteps of the beloved St. John Paul II and run the church through the fallout of the clerical sex abuse scandal and then a second scandal that erupted when his own butler stole his personal papers and gave them to a journalist.
READ MORE: Pope hopes to promote interfaith dialogue in first visit to Bahrain
Oldest elected pope
Benedict inherited the seemingly impossible task of following in the footsteps of John Paul when he was elected the 265th leader of the Church on April 19, 2005.
He was the oldest pope elected in 275 years and the first German in nearly 1,000 years.
Being elected pope, he once said, felt like a "guillotine" had come down on him.
Nevertheless, he set about the job with a single-minded vision to rekindle the faith in a world that, he frequently lamented, seemed to think it could do without God.
With some decisive, often controversial moves, he tried to remind Europe of its Christian heritage. And he set the Catholic Church on a conservative, tradition-minded path that often alienated progressives.
He relaxed the restrictions on celebrating the old Latin Mass and launched a crackdown on American nuns, insisting that the church stay true to its doctrine and traditions in the face of a changing world.
It was a path that in many ways was reversed by his successor, Francis, whose mercy-over-morals priorities alienated the traditionalists who had been so indulged by Benedict.
Conservatives in the Church looked to the former pope as their standard bearer and some ultra-traditionalists even refused to acknowledge Francis as a legitimate pontiff.
READ MORE: Thousands from around Gulf pack Bahrain stadium for Pope's Mass