Mix olives, oil, horseradish, parsley, pimiento peppers, anchovies, garlic, oregano, lemon juice and pepper in a glass or ceramic bowl to make an olive spread.

Cover and refrigerate for 8 hours, or overnight.

Cut bread in half horizontally and pull out some of the soft interior.

Drain olive spread and reserve the liquid.

Brush both sides of the bread generously with the reserved liquid, then place half of the olive spread in the hollow of one piece of the bread.

Arrange a layer of lettuce and tomatoes on top, if using, then continue with a layer of mortadella, provolone, ham and sopprasetta, alternating ingredients until you have used them all.

Finally, top with remaining olive salad and cover with the other half of the bread.

Wrap the loaf tightly in plastic wrap and arrange on a large plate.

Cover with a small plate and weigh down with several pounds of canned goods or a cast-iron skillet.

Refrigerate for at least an hour, then cut into wedges and serve.