Born in the State of Qi (
齐国 Qí guó) but served the State of Wu (
吴国 Wú guó) under King Helü (
阖闾 Hélǘ). Tradition holds he wrote 《
孙子兵法》 (Sūnzǐ Bīngfǎ, 'The Art of War') around 500 BCE — 13 chapters that became one of the
武经七书 (Seven Military Classics) and arguably the most influential strategy text in world history.