After spending more than seven decades waiting to become sovereign, Britain’s King Charles has been diagnosed with a form of cancer less than 18 months since he ascended to the throne. Buckingham Palace on Monday announced that Charles, 75, would postpone public-facing duties while he undergoes treatment but was looking forward to returning to full public duty as soon as possible.

Charles became monarch on the death of his mother Queen Elizabeth on Sept. 8, 2022, having been the longest-serving heir apparent in British history. He was crowned on May 6, 2023. Some commentators had warned that the environmental campaigner, who was never shy to give forthright views on many issues as heir, would be a radical change, upending the stoical, dedicated style of his mother.

But instead he has quietly settled into his new role, with his busy routine creating little drama. That made the announcement of his health issues all the more of a surprise. “I have been brought up to cherish a sense of duty to others, and to hold in the greatest respect the precious traditions, freedoms and responsibilities of our unique history and our system of parliamentary government,” he said in his first address as king.