In a bowl, combine peppers, olives, parsley, capers, anchovies, garlic and oregano; pour in oil and toss to combine. Cover and refrigerate overnight. Drain, reserving liquid.
Slice bread in half horizontally; hollow out insides, leaving 1 inch thick walls. Brush inside of bread with reserved liquid.
Spoon half of the pepper mixture into bottom shell. Layer with salami, provolone and mortadella, packing to edge of bread cavity. Top with remaining pepper mixture, mounting in center. Replace top half of bread; wrap well. Weigh down with can in refrigerator for 30 minutes or for up to 8 hours. Unwrap and cut into wedges.