English: Arms of de Cornwall family; Sir Richard of Cornwall: Argent, a lion rampant gules ducally crowned or a bordure engrailed sable bezantee, being the arms of his father Richard, 1st Earl of Cornwall with difference a bordure engrailed. These arms were quartered by families claiming descent from that family, including:

Tregarthin arms displayed in Branscombe Church, Devon. The heraldry here is explicable by reference to the ancestry of Joan Tregarthin, as set out by Davies in his "Parochial History of Cornwall", concerning the parish of Goran:^[1]

"At Tregarden lived John de Tregarthyn, temp Edward I, how long before I know not, after which his posterity in this place married with the great inheritrixes of Pever, Chamberlayne and Hendower, of Court, in Branell, by which last, by the Cornwalls of that place, they were lineally descended from Richard, Earl of Cornwall, King of the Romans, by his concubine Joan de Valletort, widow of Sir Alexander Oakeston".

The arms are as follows:

• 1st: Argent, two lobster's claws in saltire gules (Tregarthick)^[2]
• 2nd: Argent, a chevron between three escallops sable (Tregarthin).^[3]
• 3rd: Semee of escallops, a lion rampant (Hendower)
• 4th: A lion rampant in chief a label of three points a bordure engrailed bezantee (Plantagenet/Earl of Cornwall)
• 5th: On a bend 5 (or six) roundels (Chamberlayne)
• 6th: On a chevron three fleurs-de-lys (Pever)

This family claimed descent from a younger branch of the de Cornewall family, Barons of Burford, lineally descended from Sir Richard of Cornwall (d.1296, slain by an arrow at the Siege of Berwick), a natural son of Richard, 1st Earl of Cornwall (1209-1272), (2nd son of King John) by his mistress Joan de Bath (alias Joan de Valletort).^[4]