 The main sources on the earthquake are the works of historians John Malalas (6th century), Agathias (6th century), Theophanes the Confessor (9th century), and George Kedrenos (11th century).The earthquake severely damaged the city of Tralles (modern Aydın) and the island of Kos.Lesser damages were reported from the cities of Nicomedia (modern İzmit) and Antioch (modern Antakya).