Tear or cut bread into 1-inch pieces and place in a large bowl. Add milk and soak, crushing bread with hands until well combined.In another bowl, whisk eggs, sugar, vanilla, allspice, and cinnamon. Stir in raisins, then pour into soaked bread mixture. Combine well and let sit for 2 hours, stirring occasionally.Preheat oven to 350°F. Melt butter and grease a 13x9-inch baking dish.Transfer bread mixture to dish and bake uncovered for 45-50 minutes until set. Cool on a wire rack.