The death of Queen Elizabeth II on Sept. 8 automatically made her eldest son, Prince Charles, the new monarch at 73 years old, making him the oldest person to become king of the United Kingdom. It is said that he is keeping it safe until his eldest son, Prince William, takes over.

Royal historian Marlene Koenig said that King Charles III "knows that his time is shorter" compared to his mother, who was monarch for 70 years. But "he's gonna do the best that he can."

She told the Insider, "He is and he knows he is a caretaker for the next generation." Prince William, 40, is next in line to the British throne followed by his son Prince George.

It is said that King Charles III even alluded to his possible short reign in his first speech as monarch when he pledged to uphold constitutional principles "throughout the remaining time God" grants him.

Meanwhile, Dr. Bob Morris, an honorary senior research associate at UCL's Constitution Unit, agreed with Koenig and explained that all monarchs are "placeholders." He said that "somebody's going to replace them. There's nothing more certain than that."

Dr. Morris noted that King Charles III is no longer young and while there is no telling how long he will reign, the time he has left is believed to be helpful for Prince William and Kate Middleton to "prepare them for taking over." Koenig, on the other hand, is certain that Prince William, now Prince of Wales, will "have a long(er) reign" compared to King Charles III.

Interpretations of predictions made by Nostradamus claimed that during his reign, much of the Commonwealth will have become independent. He will be left with just the British Isles to rule and he will receive widespread disapproval that would force him to abdicate.

Likewise, prior to her death, unverified sources claimed that Queen Elizabeth II gave rules for King Charles III to follow as the new monarch. She allegedly ordered for him to only rule until the age of 80 so that only leaves him seven years on the throne. These are only speculations of course, and have not been confirmed by the royal family.

Prince William, Camilla, and King Charles III
King Charles is officially proclaimed Britain's new monarch. Photo: Reuters / POOL Reuters / POOL