John VI Kantakouzenos
Kydones was initially a student of the Greek classical scholar, philosopher and Palamite Nilos Kabasilas. Emperor John VI Kantakouzenos, a staunch follower of Palamism, the Hesychast doctrine of Gregory Palamas, had befriended Demetrios Kydones as a young man and had employed him as his Imperial Premier or Mesazon (1347–1354) at the age of 23; at the Emperor's request, Kydones began to translate Western polemical works against Islam, such as the writings of the Dominican Ricoldo da Monte Croce, from Latin into Greek, and which the Emperor John VI Kantakouzenos used as references in his own writings against Muhammad and Islam (although his own daughter was married to the Turkish Muslim Emir Orhan of Bithynia). At Emperor John VI Kantakouzenos' urging, Kydones acquired knowledge of Latin, and learned to speak, read and write it well. This led Kydones to undertake a deeper study of Latin theology, particularly St. Thomas Aquinas, and he attempted to introduce his compatriots to Thomistic Scholasticism by translating some of Aquinas' writings into Greek. John VI Kantakouzenos also encouraged him in his Latin studies and he himself read some Thomist literature. However, this put Demetrios Kydones on a journey that eventually ended with his conversion to Catholicism.