 To the west, the Tuoba Xianbei founded the Kingdom of Northern Wei in 386 and invaded the Northern Yan in 396, capturing Yuyang, Ji and other cities in You Prefecture.By 439, the Northern Wei extinguished the last of the Sixteen Kingdoms and unified northern China.During the Sixteen Kingdoms period (304-439), in addition to the You Prefecture in northern Hebei, which was successively controlled by the Later Zhao, Former Yan, Former Qin, Later Zhao and Northern Wei, several other kingdoms in other parts of China also named administrative divisions within their domain "Youzhou".