Why were the Italian states able to remain independent and prosper during the Middle Ages

first the Roman Catholic Church did everything it could to stop the rise of a powerful kingdom in Italy second, the city states that developed in Italy were about equal in strength; so although they fought many wars, no state was able to defeat all the others. Third and most importantly, the city states stayed independent because they became very wealthy. They could build large fleets and hire people (mercenaries) to fight in their armies.