郯城系郯子故里,为古郯国故地,多有文字记载,人们熟知。而在郯国之前,郯城曾为徐地,徐国在此建都,历时900余年,传位30世,有5位国君葬于郯城北7里。郯城是徐氏文化的发祥地,对于这段历史,研究的人不多。《史记》、《左传》、《东夷传》等各类史籍对徐国记载不多,洋洋一部《史记》,对徐的记述,仅寥寥数语,且多纰谬。对著名的国君徐偃王,仅提到“徐偃王作 郯 Department of town prickly heat hometown, the ancient Gu State, there are many written records, people are familiar with. Before the founding of the country, Tancheng once Xu land, Xu State capital in this building, which lasted more than 900 years, the throne 30, there are 5 monarch buried in Tancheng North 7 years. Tancheng is the birthplace of Tsui culture, for this period of history, few people research. Various historical books such as Historical Records, Zuo Zhuan and Dong Yi Chuan recorded only a few records of Xu State, a foreign history book, and a narration of Xu, with only a few words and more absurdities. The famous monarch Xu Yan Wang, only mentioned "Xu Yan Wang Zuo