The book is dedicated to Byzantine Hellenism of the 9th century. In Byzantium, interest in ancient culture has sharply increased. At the origins of this revival was the famous iconoclast John the Grammarian, and his nephew Leo the Philosopher raised a circle of disciples and followers, thanks to which a collection of manuscripts of Plato and Neoplatonists was created. The Hellenistic humanism of this era, approaching Platonism and secularism, is most vividly reflected in the work of Leo the Philosopher and his student Leo Hirosfact.