This paper discusses the comparative aspect of Charles Halperin’s biography of Ivan the Terrible. In his book, Halperin reassesses Michael Cherniavsky’s view of Ivan the Terrible as a Renaissance prince by noting that Cherniavsky overestimated the importance of Moscow-the Third Rome theory and used unreliable later sources. In Russian scholarship, according to Halperin, comparative works on Ivan iv have been marred with nationalism. One should also add here the negative impact of vulgar Marxism on Soviet comparative studies of Ivan iv. Nevertheless, a comparative approach to Ivan the Terrible is still viable because, as Halperin astutely notes, the first Russian tsar “resembled his contemporaries among foreign rulers more than he did his Muscovite predecessors or successors.” In this article I apply Halperin’s comparative methodology to Ivan iv the Terrible and Philip ii the Prudent of Spain. What Ivan and Philip had in common was not Renaissance ideas but intensive religious beliefs. The paper examines the foreign and domestic policies of both monarchs, as well as their contemporary visual representations from the perspectives of their religious views. Ivan’s and Philip’s preoccupation with their countryside residences, Aleksandrovskaia Sloboda and the Escorial respectively, is also discussed in the context of the rulers’ intensive religiosity. Despite their different confessions, Ivan iv and Philip ii were driven by aspirations for what they saw as original, simple, correct Christianity.