Samhain was a Gaelic festival marking the end of the harvest season and the beginning of winter that was celebrated by the Celts in Ireland, Scotland, and Wales on October 31. As the Roman Empire conquered Celtic lands, they incorporated aspects of Samhain into their festivals honoring Pomona, the goddess of fruit and trees. When Christianity spread in the 7th century, All Saints Day was introduced on November 1 and elements of Samhain traditions were merged with the new religious holiday. Today, Halloween customs and traditions have evolved from the ancient Celtic harvest festival of Samhain and the Christian hallowtide season.