In Celtic religion, a festival held on the first day of May, celebrating the beginning of summer and open pasturing. Beltane was one of two turning points in the year, the other being November 1 (Samhain), the start of winter. At both, the bounds between the human and supernatural worlds were erased. On May Eve, witches and fairies roamed freely, and measures had to be taken against their enchantments. As late as the 19th century in Ireland, cattle were driven between two bonfires on Beltane as a magical means of protecting them from disease. See alsoHalloween.