Once, when the Saracens landed in Cornwall shortly after the Sessoins had gone, Boudwin "raised the country privily and hastily", put wildfire in three of his own ships, caused them to be driven among the ships of the Saracens, and so burned their entire navy. Then Boudwin and his men set on the Saracens and slew them all, to the number of forty thousands. Mark went wild with jealousy and murdered Boudwin, by stabbing him in the heart with a dagger.
The character seems to have been adapted from Pernehan, Mark's doomed brother in the Prose Tristan.
Boudwin's Doublet and Shirt
Boudwin was murdered by his brother, King Mark. Boudwin's widow Anglides kept the bloody garments to give her son Alisander when he grew up and was of an age to think about avenging his father.
This is similar to Sir La Cote Male Taile's wearing the coat in which his father was murdered until he could avenge that deed.