With The Queen’s passing, many changes are happening. Upon her death on 8 September 2022, Prince Charles automatically accended the throne as King. As the eldest son and heir apparent of the reigning British monarch, Prince William, the Duke of Cambridge automatically gained the title Duke of Cornwall. Catherine, as his wife, became the Duchess of Cornwall. In Scotland, the couple will be known as The Duke and Duchess of Rothesay.
From 8 to 9 September 2022, they were known as The Duke and Duchess of Cornwall and Cambridge. This follows the precedent of King George V and his wife, Queen Mary, who were known as the Duke and Duchess of Cornwall and York from the accession of George’s father, King Edward VII, until George was created Prince of Wales on 9 November 1901.1
On 9 September 2022, King Charles II announced that he had created Prince William Prince of Wales earlier that day. This makes Catherine the new Princess of Wales.
Both the Cambridge and Cornwall titles will also remain his. The only way for Prince George to succeed his father as Duke of Cambridge would be if William died before becoming King. If William becomes King, the Cambridge title will merge with the Crown. However, the Cornwall title is reserved for the eldest son and heir apparent of the reigning British monarch, so when William is King, George will be Duke of Cornwall.