Preheat the oven to 350 degrees F. Lightly grease a glass pie plate. In a mixing bowl, beat together the cream cheese, mayonnaise, Parmesan cheese, Romano cheese, garlic, basil, and garlic salt. Stir in the artichoke hearts and spinach until well mixed. The dip can be prepared ahead of time to this step and stored in the refrigerator in a covered container for up to 48 hours. When ready to bake the dip, spoon it into the greased pie plate. Sprinkle the top of the dip evenly with the Mozzarella cheese. Place the dip in the oven and bake at 350 degrees F for 25 minutes or until the Mozzarella cheese is melted and lightly browned. Remove the dip from the oven and serve hot with toasted bread slices or crackers for dipping.