King Charles and Queen Camilla faced numerous obstacles leading up to their April 9, 2005 wedding day. Public perception of their relationship—and of Camilla Parker Bowles in general—was low given their longtime affair while Charles was still married to Princess Diana.

King Charles and Queen Camilla will pop the champagne to celebrate their 20th wedding anniversary on Wednesday at a state banquet in Rome.

As their majesties continue their tour of Italy, a royal commentator provides insight into how they have made their 20-year marriage work.