 When it did refer to the Christian Era, it was sometimes qualified, e.g., "common era of the Incarnation", "common era of the Nativity", or "common era of the birth of Christ".An adapted translation of "Common Era" into Latin as "Era Vulgaris" ("era"—or, with a macron, "ēra"—being an alternative form of "aera"; "aera" is the usual form) was adopted in the 20th century by some followers of Aleister Crowley, and thus the abbreviation "e.v.