Imbolc (also Imbolg), or St Brigid’s Day (Scots Gaelic Là Fhèill Brìghde, Irish Lá Fhéile Bríde, the feast day of St. Brigid), is an Irish festival marking the beginning of spring. Most commonly it is celebrated on 1 or 2 February (or 12 February, according to the Old Calendar) in the northern hemisphere and 1 August in the southern hemisphere. These dates fall approximately halfway between the Winter Solstice and the Spring Equinox.
The festival was observed in Gaelic Ireland during the Middle Ages. Reference to Imbolc is made in Irish mythology, in the Tochmarc Emire of the Ulster Cycle. Imbolc was one of the four cross-quarter days referred to in Irish mythology, the others being Beltane, Lughnasadh and Samhain. It has been suggested that it was originally a pagan festival associated with the goddess Brigid, who was later Christianised as St. Brigid.
In the 20th century, Imbolc was resurrected as a religious festival in Neopaganism, specifically in Wicca, Neo-druidry and Celtic reconstructionism.