Originally from Sparta, he first went to Milan where he worked as a copist and then to Paris as there was a great need for a Greek teacher and translator at the time. Hermonymus arrived at Paris in 1476, worked as a copyist at the French court.
Later, as a lecturer at the Sorbonne he took advantage of the vast collection of ancient Greek books in the libraries of Paris to start his scholarly activities. He became renowned as a teacher of Greek and among his pupils were Erasmus, Budaeus, Reuchlin and Jacques Lefèvre d'Étaples.
Hermonymus was also involved in diplomacy. In 1475 he was sent to the Kingdom of England by Pope Sixtus IV, in order to lobby for the release of George Neville from imprisonment by Edward IV of England.