The Arms of Lancelot du Lac.
It is rare to find a knightly character in medieval fiction with a universal and recognizable coat of arms (yet, the direction of the stripes is inconsistent). Even Roland didn’t get that.
Use of his arms in images seems to have fallen into disuse after the Victorians, I cannot think of a film that uses the stripes. If you’ve seen one, please let me know as I’ve seen a lot of King Arthur movies, including that terrible mess First Knight.
It amazes me that medieval people cared so much about these stories and this character that they almost universally (a tough word to use for the middle ages) gave this non-existent knight a sigil. I speaks volumes about the medieval character that his is also a tragically flawed person as well. Truly important coat of arms…
…Even if it he looks like he defends himself with a candy cane.
(Photos are from the Wikipedia Commons and are all public domain)