His most important work is easily his "Confession" ("Ekthesis tes pisteos ton orthodoxon christianon", generally known as "Homologia tou Gennadiou") addressed to Mehmed II. It contains twenty articles, of which however only the first twelve are authentic. It was written in Greek; Achmed, Qadi of Berrhoea, translated it into Turkish. This is the first (in date) of the Orthodox Symbolic books. It was published first (in Greek and Latin) by Brassicanus (Vienna, 1530), and again by Chytræus (Frankfurt, 1582). Martin Crusius printed it in Greek, Latin, and Turkish (in Greek and Latin script) in his "Turco-Græcia" (Basle, 1584 reprinted in "Patrologia Graeca", CLX 333, sqq.). Rimmel reprinted it (Greek and Latin) (in his "Monumenta fidei Eccl. Orient." (Jena, 1850), I, 1–10.); and Michalcescu in Greek only. There exists an arrangement of this Confession in the form of a dialogue in which Mehmed asks questions ("What is God?" – "Why is he called "theos"?" – "And how many Gods are there?" and so on) and Gennadius gives suitable answers. This is called variously Gennadius's "Dialogue" ("dialexis", διάλεξις), or "Confessio prior", or "De Via salutis humanæ" ("Peri tes hodou tes soterias anthropon"). Rimmel prints it first, in Latin only, and thinks it was the source of the Confession. It is more probably a later compilation made from the Confession by someone else. It should be noticed that Gennadius's (quasi-Platonic) philosophy is in evidence in his Confession (God cannot be interpreted, "theos" from "theein", etc.; cf. Rimmel. Either for the same reason or to spare Muslim susceptibility he avoids the word "Prosopa" in explaining the Trinity, speaking of the three Persons as "idiomata" "which we call Hypostases".