 A 1759 history book uses "common æra" in a generic sense, to refer to the common era of the Jews.The first use found so far of the phrase "before the common era" is in a 1770 work that also uses "common era" and "vulgar era" as synonyms, in a translation of a book originally written in German.The 1797 edition of the Encyclopædia Britannica uses the terms "vulgar era" and "common era" synonymously.