Sun Tzu proved on the battlefield that his theories were effective (for example, at the Battle of Boju), that he had a successful military career, and that he wrote "The Art of War" based on his tested expertise. However, the "Zuozhuan", a historical text written centuries earlier than the "Shiji", provides a much more detailed account of the Battle of Boju, but does not mention Sun Tzu at all. Beginning around the 12th century, some scholars began to doubt the historical existence of Sun Tzu, primarily on the grounds that he is not mentioned in the historical classic "Zuo zhuan", which mentions
Leadership trust results in folly. Dependence on the strength of courage results in violence. Excessive discipline and sternness in command result in cruelty. When one has all five virtues together, each appropriate to its function, then one can be a leader. — Sun Tzu Machiavelli's "The Prince", written in the early 16th century, provided a manual for rulers ("princes" or "tyrants" in Machiavelli's terminology) to gain and keep power.In the 19th century the elaboration of anarchist thought called the whole concept of leadership into question. (Note that the "Oxford English Dictionary" traces the word "leadership" in English only as far back