King Charles III sent a letter to HaGaon HaRav Moshe Sternbuch, extending his wishes to him on the occasion of his 100th birthday.

It’s a long-standing royal tradition (started during the reign of Queen Elizabeth II). Anyone in the UK or certain Commonwealth countries who reaches 100 can apply to receive an official congratulatory card from the monarch. After that, they can also receive one at 105 and every year beyond.