under the promise of peace, let Goujian return to Yue, his homeland which later proved to be a fatal mistake for Wu. While Wu was engaged in a military campaign in the north, Goujian enacted his revenge and launched a surprise attack on Wu in 482 BC and conquered the capital. Over the next decade, Wu was unable to recover and Yue absorbed the state in 473 BC. Wu, Yue, and Chu all proclaimed themselves kings in the 6th century BC, showing the drastic weakening of the Zhou court's authority during the Spring and Autumn period. Wu and Yue were masters of metallurgy, fabricating excellent swords with incised messages, geometric patterns, and inlaid gold or silver. Wu and Yue swords tend to use much more tin than copper compared to those of other states. Wu often sent swords as gifts to northern states, such as Qi and Cai. Examples include the spearhead of King Fuchai and the sword of Prince Guang. Kings of Wu family tree Chinese historical texts linked the kings of Wu to Taibo, the uncle of King Wen of Zhou. Their ancestral name was Ji and their clan name was Gufa. The last king of Wu, King Fuchai had at least four sons, three of whom were named You, Hong and Hui. You was his heir but was killed in one of the battles leading to the defeat of Wu, and Hong became the new heir. After the collapse of the state, the other three sons of Fuchai were exiled. Themselves, their blood relatives and descendants took Wu as their clan name in honor of their fallen kingdom. Culture The Records of the Grand Historian states that the people in Wu wore their hair short and sported tattoos. For Sima Qian this would have illustrated their supposed barbarism, as in his time Chinese men and women were not allowed to cut their hair or otherwise modify their body - doing so was considered an offence against the ancestors from which one had inherited one's physical features. Wu rulers did not receive posthumous names after death. Literature The famed military strategist Sun Tzu, renowned for his military treatise The Art of War, served as a general under King Helü of Wu. Language The rulers of Wu are said to be descendants of early Zhou, however the indigenous language of the Wu region is distinct from Old Chinese spoken