Aeneas Tacticus

Aeneas Tacticus was one of the earliest Greek writers on the art of war and is credited as the first author to provide a complete guide to securing military communications. Polybius described his design for a hydraulic semaphore system. His only surviving work, How to Survive Under Siege, covers how to defend a fortified city that is under siege. The work gives instruction to not just military commanders but also the citizens of the city under attack, providing secure communication, internal security, and how to keep morale high. This work is what credits him with having the oldest known book on defense warfare in Greek literature. He also provides a lot of insight into the politics within the classical polis.