During the third and fourth decades of the fourteenth century, at a time when the rapidly shrinking Byzantine Empire suffered greatly from internal strife, the Orthodox Church was rocked by an acrimonious controversy. This controversy ultimately led to a redefinition of traditional Trinitarian dogma as it had been formulated in late antiquity: in 1351 a church synod decreed that not only the transcendent being of God was in the true sense divine but also his operations or energies in this world, and it condemned as heretical the alternative belief that these operations were created. The decree of the synod reflects a theological model that the Athonite monk Gregory Palamas had developed in polemical encounters with a string of opponents, among whom the monk Barlaam of Calabria and the literati Gregory Akindynos and Nikephoros Gregoras were the most prominent. While these men were excommunicated, Palamas himself was canonised as a saint less than a decade after his death in 1359. Today he is considered one of the authorities of the Orthodox Church and the rediscovery of his writings by theologians of the last century has played a crucial role in the construction of present-day Orthodoxy.

The last stage of the controversy between Palamas and his adversaries was characterised through a high level of abstraction and the extensive use of patristic proof texts. However, its starting point was anything but academic. Palamas formulated his views on the divine operations in order to solve a concrete problem: namely how to reconcile the reality of mystical experiences with traditional theology, which stressed the inaccessibility of God and rejected all claims to visions of God’s being.