This book presents a chronological and thematic analysis of Spanish government during the mid-seventeenth century. It focuses on Philip IV’s bestowal of favour on a minister-favourite, don Luis Méndez de Haro, whilst also considering the wider aristocratic ministry of which he was the central figure. The early chapters discuss Philip IV’s court and government during the 1640s. The central part of the book analyses the governing elite of the Spanish Monarchy within its legal, institutional, and geographical frameworks. The last two chapters shift the focus towards foreign policy, presenting a new reading of the closing stages of Spain’s war with France, one in which the dogged pursuit of this conflct is shown to have been intrinsic to the survival of the favourite’s regime, and was to an important degree brought to an end by the unauthorised actions of other ministers who had finally decided that enough was enough.