VATICAN CITY, VATICAN - APRIL 04:  Pope Francis meets with Prince Charles, Prince of Wales and Camilla, Duchess of Cornwall on April 4, 2017 in Vatican City, Vatican. (Photo by Tim Rooke - Pool / Getty Images)
ROME, ITALY - APRIL 04:  (C 2nd R) Cardinal Peter Turkson, Prince Charles, Prince of Wales, British Ambassador to the Holy See Sally Axworthy and Foreign Office Minister Sir Alan Duncan attend a meeting on climate change in Rome on the seventh day of Charles' European tour on April 4, 2017 in Rome, Italy.  (Photo by John Stillwell - Pool / Getty Images)
VATICAN CITY, VATICAN - APRIL 04:  Pope Francis exchanges gifts with Prince Charles, Prince of Wales and Camilla, Duchess of Cornwall during an audience on April 4, 2017 in Vatican City, Vatican. Prince of Wales and Duchess of Cornwall are in Italy for a six day visit.  (Photo by Vatican Pool/Getty Images)
Britain's Prince Charles, Prince of Wales, unveils a sculpture by Henry Moore to mark the Centenary of the British Institute at the Palazzo Strozzi in Florence, on April 3, 2017 as part of a six-day visit to Italy and Vatican.  / AFP PHOTO / Alberto PIZZOLI        (Photo credit should read ALBERTO PIZZOLI/AFP/Getty Images)
VATICAN CITY, VATICAN - APRIL 04:  Prince Charles, Prince of Wales and Camilla, Duchess of Cornwall visit the Vatican Apostolic Library before a private audience with Pope Francis at the Vatican on April 4, 2017 in Vatican City, Vatican. The royal couple ihave been in Italy for a five-day visit during which they visited the city of Florence, Camilla visited the city of Naples and the ancient archaeological site of Herculaneum, while Prince Charles, visited Amatrice, the town devastated by a 6.0 magnitude earthquake and where 297 people died last summer. (Photo by Vatican Pool - Corbis/Corbis via Getty Images)