In the 13th century BC, the state of Zhou (which will later become the Zhou Dynasty) was ruled by Tai Wang (King Tai of Zhou). His surname was originally Ji (). He had three sons: Taibo, Zhongyong, and Jili. King Tai of Zhou favored the youngest son, Jili to inherit the reins of power, therefore Taibo and his brother Zhongyong voluntarily left Zhou with a group of followers and headed southeast where they established the state of Wu. Taibo and Zhongyong's descendants eventually adopted Wu () as their surname. The state of Wu, which later claimed to be a kingdom of its own, was best known for its military prowess as Sun Tzu, the author of the famed book "The Art of War", was the country's general serving under King Helü of Wu. Wu is also generally attributed to developing the first Chinese Navy. This Navy was quite complex and had different classes of ships. These "classes" of ships were the great wing (da yi), the little wing (xiao yi), the stomach striker (tu wei), the castle ship (lou chuan), and the bridge ship (qiao chuan). These were listed in the "Yuejueshu" ("Lost Records of the State of Yue") as a written dialogue between King Helü of Wu (r. 514 BC–496 BC) and Wu Zixu (526 BC–484 BC) in which the latter stated: