  Metochites discussed philosophy in some of his orations (Logoi) and some of his hexameter poetry. Dodecasyllabic verse was also put to use, notably by John Tzetzes (c. 1110–1180), who wrote a 1700-line paraphrase of Porphyry’s Isagoge. The Byzantines are also known for having enthusiastically cultivated the art of writing letters, in which they occasionally dealt with philosophical questions (e.g., Michael Psellos, Letter to Xiphilinos; Theodore Prodromos, On ‘Great’ and ‘Small’).