Catholic Spain is usually identified, even by professional historians, with the Counter Reformation, as far as the supposedly "golden age" of Philip II and Philip III is concerned. This study examines not the foreign policy of Habsburg Spain, in its naval and military campaigns against militant Islam and Protestant heresy, but the reality of Catholic practice in the Iberian peninsula itself. Certain features of Spanish religion, such as the insistence on orthodoxy combined with a persistent anti-clericalism, are traced to this crucial period in the development of Catholicism in Spain. NonInquisitorial as well as Inquisitorial evidence is drawn on and Roman archival sources are used in addition to documents from Spain itself. This work thus seeks to analyze Spanish Catholicism during the period of the Counter-Reformation not in a traditional way, as part of Spanish history in isolation; but as a distinct part of the Catholic Church as a whole, in the era of post-Tridentine reform, taking as reference-points recent work on that larger subject by scholars not only in Spain but in other countries also, such as France and Italy.