This book presents a study of the later years of the reign of Philip IV from the perspective of his favourite (valido), don Luis Mendez de Haro, and of the other ministers who played a role in the government of the Spanish Habsburg Monarchy. It offers a positive vision of a period that is often seen as one of failure and decline. Unlike his predecessors, Haro exercised the favour that he enjoyed in a discreet way, acting as a perfect courtier, and honest broker between the king and his aristocratic subjects. Nevertheless, there was still a major problem, because the rulers delegation of his authority to a single nobleman was considered by many to have been incompatible with good kingship, and Philip IV was himself very uneasy about failing in his responsibilities. Haro was thus in a highly insecure situation, and sought to justify his regime by acting as the manager of a prestigious and expensive foreign policy. In this context, the eventual realization of an honourable peace with France in 1659 is shown to have been as much the result of the independent actions of other ministers, like the counts of Penaranda and Fuensaldana, as it was of a royal favourite who had been very reluctantly brought to the negotiating table at the Pyrenees. In the concluding chapters the quite sudden collapse of Spanish European hegemony after Haros death in 1661 is represented as a delayed reaction to the repercussions of a flawed system of government.