Causality and the Procession of the Holy Spirit in Manuel Kalekas’s De fide deque principiis catholicae fidei

Abstract This article examines the way in which Manuel Kalekas describes the procession of the trinitarian persons in one of his earliest systematic treatises. As a member of so-called “Kydones circle,” Kalekas was part of a fourteenth-century group of Latinophrone Byzantine theologians who were interested in ecclesial union with the Latin West and in Latin theological sources. In addition to certain texts from Augustine, during the fourteenth century several works by Thomas Aquinas became available in Greek translation. Kalekas’s De fide is of interest because it integrates conceptual and structural insights from Aquinas even as it draws on Greek traditions from Cappadocia and Byzantium. Although the importance of Aquinas’s Summa contra gentiles for the work of the Kydones circle is often cited, this article argues that Aquinas’s Summa theologiae was also a significant influence for Kalekas.