Deydras, who was working as a clerk in Oxford at the time, did apparently bear a striking resemblance to the current King, Edward II. He was equally as strong and tall as the king, but Deydras was missing an ear.

This missing ear, he claimed, was the key to understanding his claim to the throne. Deydras claimed that while he was a baby a careless servant had allowed him to be savaged by a sow. The sow bit off his ear, and the horrified servant was so afraid of the punishment she would receive for her neglect that she swapped the royal baby (Deydras) with the baby of another servant and managed to successfully pass this low-born baby off as the son of Edward I. The servant's subterfuge was never found out and the swapped baby was raised to be King, while Deydras, the true heir to the throne, was raised in poverty.

According to the Lanercost Chronicle, Deydras "declared that my Lord Edward was not of the blood royal, nor had any right to the realm, which he offered to prove by combat to him". A risky claim to make to say the least!

Despite the seeming implausibility of Deydras's claims, as word of them spread they did begin to gain some traction. Edward II was not a universally popular king, having lost the Battle of Bannockburn, feuded with his cousins, and alienated the Barons. His interest in the life of the common man had also been commented on, particularly his interest in such 'low' occupations as thatching and ditch-digging. Could this be a sign that Edward II was truly a changeling, a commoner in disguise?

It appears that Edward II did not take Deydras's claims at all seriously. When Deydras was brought before him at the Northampton parliament in August, the King jokingly greeted him with "Welcome, my brother!" and suggested that Deydras could be kept around to act as a court jester.

Edward II's wife Isabella, however, did not see the funny side. Whether she saw Deydras as a genuine threat to her husband's legitimacy, or merely a public embarrassment, is not clear. What is clear is the result, John Deydras was charged with sedition and thrown into prison.

At Deydras's trial his story took an even more bizarre turn. Under questioning, Deydras admitted that he had made the whole story up, put pointed the finger of blame at his pet cat! He claimed that the Devil has started speaking to him through the cat one day whilst he was walking across Christchurch meadow. He claimed that it was the Devil-cat who had encouraged him to make his claims.

The idea of the Devil speaking through a cat may seem crazy today, but in the 14th century, with rumours of witchcraft abounding in Europe, the authorities were not taking any chances. Deydras was hanged at Northhampton, and his cat was hanged beside him.

A sad end for what was clearly a deeply troubled young man (and innocent cat), though an end that was definitely preferable to the death rumoured to have been experienced by Edward II himself!