The Art of War is an ancient Chinese military treatise dating from the Late Spring and Autumn Period (roughly 5th century BC). The work, which is attributed to the ancient Chinese military strategist Sun Tzu ("Master Sun", also spelled Sunzi), is composed of 13 chapters. Each one is devoted to an aspect of warfare and how it applies to military strategy and tactics. For almost 1,500 years it was the lead text in an anthology that would be formalised as the Seven Military Classics by Emperor Shenzong of Song in 1080. The Art of War remains the most influential strategy text in East Asian warfare and has influenced both Eastern and Western military thinking, business tactics, legal strategy and beyond.