Saint Leontius of Monemvasia or Saint Leontius of Achaia, was an Eastern Orthodox Saint born in Monemvasia in 1377 and lived in asceticism in the region of north Peloponnese in the 15th century. Details about his life are known mainly from his first biographer, who, according to some scholars, is the Byzantine philosopher and Ecumenical Patriarch of Constantinople, Gennadius Scholarius.