The Warring States Period was a time of intense conflict in ancient China from about 475 to 221 BCE. During this era, several powerful states fought for dominance after the decline of the Zhou Dynasty. Each state sought to expand its territory and influence, leading to constant battles and shifting alliances. This period saw significant developments in military strategy and philosophy, with thinkers like Sun Tzu emerging. His famous work, the Art of War, emphasized tactics and the importance of understanding both oneself and the enemy. Ultimately, the Warring States Period ended when the Qin Dynasty unified China, marking the beginning of a new era.