Vert (heraldry) medieval figurative art. The Anglo-Norman "prose Brut" (c. 1200) has Brutus of Troy bear a green shield, "Brutus Vert-Escu, Brutus Viride Scutum". Green is occasionally found in historical coats of arms (as opposed to the fictional "green knights" of Arthurian romance) from as early as the 13th century, but it remained rare, and indeed actively avoided, well into the 15th century, but becomes more common in the classical heraldry of the 16th and 17th centuries. An early example of a green escutcheon was that of the coat of arms of Styria, based on the banner of Ottokar II of Bohemia
Star (heraldry) Register, vol 1 p 188), while the Ordinary of Arms produced by a late 19th century Lyon King of Arms 'modernizes' the original as "Az. three mullets arg. ...". In Canadian heraldry the usual term is "mullet", but there is also the occasional six-pointed "star" (e.g. in Vol. IV, at p. 274 and in online version of the Canadian Public Register), which is what others would blazon as a six-pointed "mullet". The United States Army Institute of Heraldry, the official heraldic authority in the United States, uses the term "mullet" in its blazons, but elsewhere, as in US government documents