In a medium-size bowl, mix together olives, tomato, olive oil, celery, garlic, vinegar, oregano, parsley and pepper. Cover and refrigerate 1 hour.
Spoon 1 cup of the olive mixture over the bottom half of the bread. Layer on salami, provolone, turkey and American cheese. Top with remaining olive mixture. Cover with top of bread. Wrap in plastic and place on baking sheet. Weight down with heavy pot. Let stand 1 hour at room temperature. If desired, remove plastic and cut into 8 wedges. Place wedges back together to form round and rewrap in plastic. Refrigerate until ready to serve.
Makes 8 servings.