Defining the boundaries of authority became paramount during the development of both secular governments and the hierarchy of the Catholic Church in the Middle Ages, resulting in frequent negotiations to outline the power relationship between church and state. In the early Middle Ages both popes and kings often needed help acquiring legitimacy and so entered into mutually beneficial alliances. As papal power expanded and kings became more secure as members of dynastic lineages, however, church and state often clashed. The resulting negotiations ultimately served as the foundation for the modern American and European belief that secular authority should be separate from, though respectful of, religious authority.