By late July, the now crowned Richard III began a progress through England with his royal entourage. He'd left behind him people paid to guard the boys. It can be assumed that they were safe and sound, just hidden indoors, around this time.
The Duke of Buckingham had been one of Richard's closest friends and allies. He was included in the grand tour of the country. But in Gloucester, the two of them violently quarreled over some unknown cause.
By the time that Richard reached Warwick, on August 8th 1483, the Duke of Buckingham had left his company. He'd used a flimsy excuse to check on his lands in the Welsh Marches. Buckingham promptly raised one of the most serious rebellions of Richard's reign.
He did it initially in the name of Edward V, whom Buckingham sought to return to the throne. In short, whatever they argued about, Richard's closest friend believed the boy to still be alive in early August.
However, by the autumn, Buckingham's uprising swiftly changed gears. He suddenly and without ceremony ditched his bid to return Edward. Instead his allegiance went to Henry Tudor (a man with less claim to the throne than Buckingham himself). What had he heard (or done) to make him opt for the long shot?
Most damning of all, around the same time, Elizabeth Woodville also had a change of heart. She had begun negotiating with Margaret Beaufort, attempting to gain Tudor support for Edward V. The idea was to marry her daughter, Elizabeth of York, to Henry Tudor to secure the deal.
That plan ultimately did go ahead. The couple became the founders of the Tudor dynasty. But Elizabeth Woodville's motivation had also flipped in the autumn of 1483. Now it wasn't allegiance for her son that she wanted, but her daughter on the throne.
She had some knowledge which assured her that her sons were dead. But she never once stated that it was murder. Unlike York refugees on the continent, or the later Tudor propaganda machine, such rumors didn't even appear that current in 1483.
It wasn't until January 1484 that anyone openly accused Richard III of killing, or ordering the murder, of his nephews. The York King merely kept silent, even while his reputation took a battering. It would have been so much easier for him to have produced them to prove that they were alive.
That he didn't is perhaps the strongest indication of all that they were not.
The great Medieval mystery remains - if they were dead, then how did they die? Unfortunately, it's a question that seems unlikely ever to be answered.