The festival that honors the harvest and has roots in ancient Celtic traditions is Samhain. Celebrated around the end of October, Samhain marked the transition into winter and the start of the new year in the Celtic calendar. It was a time for communities to gather, acknowledge the end of the harvest season, and celebrate the coming dark months. Traditions included lighting bonfires, offering sacrifices, and engaging in rituals to honor ancestors and ward off spirits. The festival has heavily influenced modern Halloween customs.