King Charles III, the new monarch
At the moment the Queen died, the throne passed immediately and without ceremony to the heir, Charles, the former Prince of Wales.
But there are a number of practical - and traditional - steps which he must go through to be crowned King.
What will he be called?
He will be known as King Charles III.
That was the first decision of the new king's reign. He could have chosen from any of his four names - Charles Philip Arthur George.
He is not the only one who faces a change of title.
Although he is heir to the throne, Prince William will not automatically become Prince of Wales - that will have to be conferred on him by his father. He has inherited his father's title of Duke of Cornwall - William and Kate are now titled Duke and Duchess of Cornwall and Cambridge.
There is also a new title for Charles' wife, Camilla, who becomes the Queen Consort - consort is the term used for the spouse of the monarch.