Yan, a vassal state of Zhou in present-day Hebei and Liaoning, north Hebei, the four Yan kingdoms of the Sixteen Kingdoms, namely: Former Yan 前燕[Qian2 Yan1] (337–370), Later Yan 後燕|后燕[Hou4 Yan1] (384–409), Southern Yan 南燕[Nan2 Yan1] (398–410), Northern Yan 北燕[Bei3 Yan1] (409–436), surname Yan