Sun Tzu (also known as Sunzi, personal name Sun Wu) was a Chinese military strategist, philosopher, and writer best known as the author of the classic work The Art of War (also known as The Thirteen Chapters), the earliest known treatise on war and military science. He lived in the Eastern Zhou period of ancient China. His magnum opus has had a deep influence on both Western and East Asian philosophy when it comes to matters regarding military strategy. His strategies often focused on alternatives to battle, including the use of spies, building alliances with allies, using deceit, stratagem, and a willingness to temporarily submit to powerful foes. He is regarded as a legendary figure in the world history of the military, especially more so in Chinese and East Asian culture. Popular since the time it was first published, The Art of War saw a resurgence in popularity during the 20th century. Besides military strategy, the tactics mentioned in the book have now found practical use in varied competitive fields, such as politics, business, and sports. Despite the resounding fame of the book, not much is known about the personal life of the author. Traditional Chinese historians, including Han dynasty historian Sima Qian, stated he was probably a minister to King Helü of Wu and lived during 544-496 BC.