Its navy not only protected it from invasion , but ruled supreme in Aegean waters .
About 535 BC , when the existing oligarchy was overturned by the tyrant Polycrates , Samos reached the height of its prosperity .
Samos ' navy not only protected it from invasion , but ruled supreme in Aegean waters .
About 535 BC , when the existing oligarchy was overturned by the tyrant Polycrates , Samos reached the height of its prosperity .