According to a Welsh tradition, Edward I. promised to provide Wales with a prince “who could speak no word of English,” and when his sonEdward of Carnarvon was born he presented him to the assembly, saying in Welsh Eich dyn (behold the man).
The more general belief is that it was the motto under the plume of John, King of Bohemia, slain by the Black PrinceatCressy in 1346, and that the Black Prince who slew the Bohemian assumed it out of modesty, to indicate that “he served under the king his father.”