Maxim (or Maximus, b. 1475) began his life in Greece and after completing some studies there, he traveled to Italy to further his education. There he was attracted to Neoplatonism and to the Dominican preacher Girolamo Savonarola. This led him to eventually (but briefly) becoming a Dominican, in 1501, leaving the order around 1504. He ended up returning to Greece, becoming a monk on Athos, and was later sent to Russia to fulfill a request by the Grand Prince to translate some texts. In his time in Russia, he never seems to have revealed his Dominican past (never, e.g., mentioning Aquinas), but he did show the extensive learning characteristic of the Order of Preachers and he was also much more moderate in his criticisms of the Latins than were most Russians. Due to his support of the Non-possessors and unfavorable political circumstances, he was eventually imprisoned and died in 1556.
Thus the Latins, although in many ways they have yielded to temptation and invented certain strange doctrines, having been tempted by their own great learning in the Greek sciences, nevertheless have not finally fallen away from faith, hope, and love for Jesus Christ, and therefore those among them who have dedicated themselves to the monastic life assiduously order their service to God according to His holy commandments, since their harmony of belief, brotherly love, non-possessorship, silence, lack of concern for worldly things, and care for salvation in many ways ought to be imitated by us, so that we would not show ourselves worse than they. This I say in respect of the assiduous fulfillment of the commandments of the Gospels.
The above is taken from Treadgold’s The West in Russia and China, vol. 1 (London: Cambridge University Press, 1973), pp. 15-16. Sadly the footnote pointing to the source in Maxim’s works is not available in the Google Books preview. Although his favorable observations of Roman Catholics were not really well received among the Russians, Treadgold reports that even after his imprisonment and death, Maxim was widely considered fully Orthodox. It might be added to this quote that he did criticize Western theology, but this was primarily aimed at the later Nominalist schools rather than writers like Aquinas (according to Marcus Plested in Orthodox Readings of Aquinas, he does disparage Scotus and Albert the Great but he never speaks about Aquinas). Additionally, he defended the Inquisition and believed the bishop of Rome to be the successor to Peter (though he believed post-schism popes to be in heresy).