King Charles III has spoken of his "deep sadness" following the death of Pope Benedict XVI on Saturday morning.

Benedict, who was the predecessor to Pope Francis, passed away at the age of 95 following a rapid decline in his health in the last few days due to old age. 

King Charles recalled "with fondness" meeting Benedict at the Vatican in 2009. 

The King said Benedict's papal visit a year later in 2010 "was important in strengthening the relations between the Holy See and the United Kingdom". 

"I also recall his constant efforts to promote peace and goodwill to all people, and to strengthen the relationship between the global Anglican Communion and the Roman Catholic Church," the King added in a letter to Benedict's successor, Pope Francis. 

Benedict was only the second Pope in history to visit the UK in 2010. 

It was a historic visit in which he met the late Queen in Scotland, addressed the then Prime Minister David Cameron and parliamentarians in the Palace of Westminster, and beatified Cardinal Newman in a Mass attended by 50,000 people at Cofton Park in Birmingham.