Wyvern folklore is rarely fire-breathing like the four-legged dragon. Sometimes modern fantasy book and media authors have wyverns that are frost-breathing or poison-breathing instead of fire-breathing. The current spelling "wyvern" is not attested before the seventeenth century as "winged two-footed dragon". According to the Oxford English Dictionary, it is an alteration of Middle English "wyver" (attested thirteenth century), from Anglo-French "wivre" (cf. French "guivre" and "vouivre"), which originate from Latin "vīpera", meaning "viper", "adder", or "asp". Conversely, medievalist William Sayers proposes a more complex origin for the term. He notes that the Anglo-French "guivre" and its Middle English derivative ceased to
Wyvern modern fantasy fiction, though its first literary appearances may have been in medieval bestiaries. The wyvern is a frequent charge in English heraldry and vexillology, also occasionally appearing as a supporter or crest. A white ("Argent") wyvern formed the crest of the Borough of Leicester as recorded at the heraldic visitation of Leicestershire in 1619: "A wyvern sans legs argent strewed with wounds gules, wings expanded ermine." The term "sans legs" may not imply that the wyvern was "without legs", rather that its legs are not depicted, being hidden or folded under. This was adopted by the Midland Railway in