Yan was a vassal name in the Spring and Autumn Period and the Warring States Period, which was located in today's Hebei Province and Liaoning Province. The capital of Yan is Ji (now Jixian County, Beijing), so it is sometimes called Yanjing. Yan played an important role in the ancient history of China and had a far-reaching impact on the development of China's history and culture. However, it should be noted that there was no province called Yan in modern China. Yan State (bronze inscription "Wei State") (65438 BC+0044 BC-222 BC) was one of the vassal states of the Zhou Dynasty, and its ancestor was Zhao Gong, the eldest son of Zhou Wenwang and one of the seven heroes of the Warring States.