The theology of St Gregory Palamas (1296—1359) is centered around the problem of the "knowledge of God". Before the "hesychast controversy" began, there was the debate with Barlaam, a Greek monk from Calabria, on the Procession of the Holy Spirit (the much discussed problem of the Filioque), which dealt with the question whether or not man is able to know anything concerning the Holy Spirit. Barlaam, basing his arguments on the apophatic theology of Dionysius the Areopagite (today referred to as "Pseudo-Dionysius"), argued that man is not able to say anything that is certain or definite concerning the