King Charles III's coronation on May 6, 2023, stirred speculations that he chose it out of spite for Prince Harry because the date also falls on his son Archie's fourth birthday. But a royal author said the decision was made based on historical processes.

Biographer Duncan Larcombe, who wrote "Prince Harry: The Inside Story," slammed accusations that His Majesty picked the same date as his grandson's birthday for his coronation as a swipe at his youngest son. He insisted that the 73-year-old has no "ulterior motive" against the Duke of Sussex.

He told OK! magazine, "The people that are seeing this as some kind of deliberate snub to both Harry and Archie are barking up the wrong tree. Anyone who has ever organised a major event – whether that be a wedding or an anniversary– knows that you'll never be able to please everyone on the guest list. Someone will always take offence."

Larcombe added that "in all honesty, King Charles III would have likely been in hotter water with the public if he hadn't checked that his Coronation wouldn't clash with the FA Cup Final."

The royal author stands firm in his defence of the new monarch and explained, "It will have been one of those situations where those in charge will have thrown multiple diaries together - that of the King, of religious leaders and of government officials – and decided on this date."

He noted, "We're in relatively unchartered territory in that there is no one still in office that can remember what happened during the last Coronation of 1953, but at the same time, there will have been historical processes to follow."

Larcombe claimed that people are reading too much into the date and accused them of only adding fuel to speculations of a rift between King Charles III and his youngest son.

Larcombe's defence of King Charles III's coronation date came after royal commentator Katie Nicholl denied that it is a snub to Prince Harry and Meghan Markle. She called it a "happy coincidence" instead. The coronation will be at Westminster Abbey in London with 2000 guests expected to attend. It is unclear if the Duke and Duchess of Sussex will choose to go or celebrate Archie's birthday in California.

King Charles III
King Charles III's coronation date is set for May 6, 2023, the same day as his grandson Archie's birthday. POOL via AFP / Ben Stansall