The festival of Imbolc (also Imbolg), now often called St Bride's Day or Candlemas after the forcible Christianization of Europe, falls today at the beginning of February. But the Gaelic people did not mark February as we do. Called in Gaelic faoilleach, or faoillteach, as we read in MacBain (1911), the month extended from the middle of modern January to the middle of our February. The word derives from the Irish faoillidh or faoilleach, meaning holidays or carnival, which itself means 'wolf-month' from faol, 'wolf'. According to McBain, February in Irish is mí na Féile Bríghde, or Lá Fhéile Bríde (Lá Feabhra), pronounced law ay-leh bree-djeh (law feow-rah). We take our name for this month from the Roman purification ritual of Februa, derived from the Latin februum, 'purification', which was held on the 15th of February by the old Roman calendar.
The name Imbolc comes from the Old Irish i mbolg, 'in the belly', apparently in reference to either pregnant ewes or milking. The oldest etymology, that of the ninth century Cormac's Glossary, derives imbolc (also oimelc) from 'the time the sheep's milk comes'. Whilst often criticised as a fanciful derivation by scholars, this has come to dominate interpretations of this festival. Within Gaelic culture the festival itself is clearly a veneration of the pre-Christian goddess Bride or Brigid and most of the recorded customs centred around this deity. Consequently, most references to this festival historically used the name of Bride or Brigid.
The festival's popularity in Wicca arose from the work of Gerald Gardner. However, Gardner had no access to authentic Pagan witchcraft sources (despite his claims) and based the ritual for what he called 'February Eve' on the general schema he had developed for ordinary coven meetings. Developed sometime between 1949 and 1953 this bare outline has since been fleshed out by other Wiccan writers, often drawing on the greater availability of scholarship on the customs and traditions of the Gaelic and Celtic peoples.