Halloween originated from the ancient Celtic festival of Samhain, where people would wear costumes, usually related to animals, and light bonfires. When the Romans conquered the Celts in 43 BC, they combined their own festival of Pomona with Samhain. After Christianity became dominant, the celebration was renamed All Hallows' Eve and Halloween. Modern traditions such as trick-or-treating are descended from medieval practices of the poor going door-to-door seeking food or money.