Pope Benedict XVI, who became the first pope in 600 years to resign, has died at the age of 95.
A statement from the Vatican on Saturday morning read: "With pain I inform that Pope Emeritus Benedict XVI died today at 9:34 in the Mater Ecclesia Monastery in the Vatican. Further information will be released as soon as possible."
The former pontiff stepped down in 2013 in a historic move, claiming his health wouldn't allow him to continue in the role.
He was then succeeded by Pope Francis.
The two lived next to each other at the Vatican with the current pope visiting him regularly.
Known as a deep thinker, Benedict will be remembered for his writings which impacted many.
He openly spoke of never wanting the role of pope going as far as saying his election felt like a guillotine had come down on him.
Despite his reservations, he served diligently for eight years.
Tributes have been said from across the world, both inside and outside the Church.
Cardinal Vincent Nichols, the head of the Roman Catholic Church in England and Wales, said: "I am deeply saddened to learn of the death of Pope Benedict. He will be remembered as one of the great theologians of the 20th century.
"I remember with particular affection the remarkable Papal Visit to these lands in 2010. We saw his courtesy, his gentleness, the perceptiveness of his mind and the openness of his welcome to everybody that he met."
"He was through and through a gentleman, through and through a scholar, through and through a pastor, through and through a man of God - close to the Lord and always his humble servant."
"Pope Benedict is very much in my heart and in my prayers. I give thanks to God for his ministry and leadership."
Archbishop of Canterbury Justin Welby also praised his teachings.
"Pope Benedict was one of the greatest theologians of his age," he said. "He was committed to the faith of the Church and stalwart in its defence.
"In all things, not least in his writing and his preaching, he looked to Jesus Christ, the image of the invisible God. It was abundantly clear that Christ was the root of his thought and the basis of his prayer.
Prime Minister Rishi Sunak tweeted: "I am saddened to learn of the death of Pope Emeritus Benedict XVI.
"He was a great theologian whose UK visit in 2010 was an historic moment for both Catholics and non-Catholics throughout our country.
"My thoughts are with Catholic people in the UK and around the world today."
Professor Francis Davis is head of Digby Stuart College - the Catholic college at Roehampton University.
Speaking to Premier he explained how the late pope will be remembered.
"As an intellectual - he wrote many books which changed people's lives, as a pastor at a local level and as a man who was really keen to get the Christian voice back out into the public square."
Catholic writer Andrea Gagliarducci is based at the Vatican.
Speaking to Premier about the pope's impact, he said: "People came to the general audiences but they didn't come to see the pope - they came to listen. There's a huge difference.
"They wanted to listen to what he said because his words impacted people more than we think."
The Pope's body will lie in state at Saint Peter's Basilica from Monday so Catholics can visit to pay tribute.
While funeral preparations are underway, no date has been given.