After the authority of the Zhou king declined during the Spring and Autumn period in the 8th century BC, Yan survived and became one of the strongest states in China.[6] In the 11th century BC, Yan's capital was based in what is now Liulihe Township, Fangshan District, Beijing, where a large walled settlement and over 200 tombs of nobility have been unearthed.At the turn of the 3rd century BC, General Qin Kai launched a series of campaigns against the Donghu and Gojoseon, expanding the kingdom's frontiers nearly one thousand kilometers east to northwestern Korean Peninsula.A Great Wall was constructed on Yan's new northern borders, and five commanderies, Shanggu, Yuyang, Youbeiping, Liaoxi and Liaodong, were subsequently established for the defense against the Donghu.Led by the brilliant tactician Yue Yi, it was highly successful and within a year most of Qi's seventy walled cities had fallen, with the exception of Zimu and Lu.Crushing the bulk of the Yan army at the frozen Yi River, Ji fell the following year and the ruler, King Xi, fled to the Liaodong Peninsula.Liu Bang (later Emperor Gaozu of Han) sent Fan Kuai and Zhou Bo to put down the rebellion, and they captured and executed Zang Tu.Lu Wan became the new King of Yan and reigned there for most of Liu Bang's life, until the emperor discovered that he had sent officials to the courts of the rebel Chen Xi and the Xiongnu chanyu Modu.Summoned to the imperial court, Lu Wan feigned illness and then fled to the Xiongnu, who honored him as the King of the Eastern Nomads (Donghu) until his death.Yan is represented by the star Zeta Capricorni in the "Twelve States" asterism, part of the lunar mansion "Girl" in the "Black Tortoise" symbol.