Onasander

Onasander (or Onosander) was a Greek philosopher of the first century AD. The Suda says he was a Platonic philosopher, and Onasander dedicates his treatise to Quintus Veranius, consul in 49 AD, which dates the work to the mid-first century.

His surviving work, the Strategicus (The General), is a treatise on the qualities and duties of a military commander. Unlike purely tactical works, the Strategicus is concerned primarily with leadership: how to select a general, how to maintain morale, how to handle allies, how to manage camp discipline, when to fight and when to avoid battle. The advice is philosophical in the broadest sense — Onasander draws on historical examples and ethical principles rather than technical military doctrine.

The work was remarkably influential. It was translated into Latin and used in the Byzantine military tradition. Emperor Maurice's Strategikon and Leo VI's Tactica both drew on it. For a work by an obscure philosopher, its practical afterlife has been extraordinary.