The old Celtic festival of Imbolc (Imbolg) is traditionally celebrated on January 31st / February 1st. It is a Cross Quarter Festival, midpoint between the Winter Solstice and the Spring Equinox. However when calculated astronomically, the date this year would actually be February 3rd. At the Mound of the Hostages on the Hill of Tara the rising sun at Imbolc illuminates the chamber. The Mound of the Hostages at Tara is a Neolithic Period passage tomb, contemporary with Newgrange which is over 5000 years old, so the Cross Quarter Days were important to the Neolithic (New Stone Age) people who aligned the chamber with the Imbolc and Samhain sunrise. In early Celtic times around 2000 years ago, Imbolc was a time to celebrate the Celtic Goddess Brigid (Brigit, Brighid, Bride, Bridget, Bridgit, Brighde, Bríd). Brigid was the Celtic Goddess of inspiration, healing, and smithcraft with associations to fire, the hearth and poetry. http://www.boynevalleytours.com/hill-of-tara.htm