Sun Tzu was a Chinese military general, strategist, philosopher and writer of the Eastern Zhou period, traditionally credited as the author of The Art of War, the classical Chinese text on military strategy. The name by which the world knows him is in fact an honorific meaning Master Sun; his birth name was said to be Sun Wu.
Here is the honest complication: his historical existence is uncertain. Traditional accounts, including that of the Han dynasty historian Sima Qian, placed him as a minister to King Helu of Wu and dated his life to 544 to 496 BC, yet the earliest parts of the text he is credited with probably date to at least a century after him. A descendant, Sun Bin, wrote his own treatise under the same title, and for centuries some historians thought the two men were one. None of this has dented his standing: he remains a revered, semi-legendary figure across Chinese and East Asian culture.