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
Ecclesiastical heraldry Ecclesiastical heraldry Ecclesiastical heraldry refers to the use of heraldry within the Christian Church for dioceses and Christian clergy. Initially used to mark documents, ecclesiastical heraldry evolved as a system for identifying people and dioceses. It is most formalized within the Catholic Church, where most bishops, including the Pope, have a personal coat of arms. Clergy in Anglican, Lutheran, Eastern Catholic and Eastern Orthodox churches follow similar customs, as do institutions such as schools and dioceses. Ecclesiastical heraldry differs notably from other heraldry in the use of special insignia around the shield to indicate rank in a church or denomination.