E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Brawn.
The test of the brawn’s head. A little boy one day came to the court of King Arthur, and, drawing his wand over a boar’s head, declared, “There’s never a cuckold’s knife can carve this head of brawn.” No knight in the court except Sir Cradock was able to accomplish the feat. (Percy’s Reliques.)
