So, I decided with the help of good old wikipedia of all things, that it is a Heraldic badge.
A heraldic badge is an emblem or personal device worn as a badge to indicate allegiance to or the property of an individual or family. Medieval forms are usually called a livery badge, and also a cognizance. They are para-heraldic, not necessarily using elements from the coat-of-arms of the person or family they represent, though many do, often taking the crest or supporters. Their use was more flexible than that of arms proper, and it has been suggested that escape from the increasing rigidity of heraldic regulation was a major reason for their popularity.
Badges worn on clothing were common in the late Middle Ages, particularly in England. They could be made of base metal, cloth or other materials and worn on the clothing of the followers of the person in question; grander forms would be worn by important persons, with the Dunstable Swan Jewel in enamelled gold a rare survivor of the most splendid sort.
You people are too smart for tumblr XD