城狐社鼠：隐喻依仗别人的势力胡作非为的坏人，一时难以驱除的小人。关于汉字的历史资料，城狐社鼠这个成语有着悠久的故事背景。

在晋朝时期，统治阶级非常注重门阀制度，世家贵族与新兴贵族的地位相差悬殊。在山东临沂王家是享誉海内的世家大族之一。王家的后起之秀王敦就娶了晋武帝女儿襄城公主为妻。

晋室南渡后失去了对北方的统治权。于是司马睿在南方称孤道寡，建立东晋王朝定都建康（今南京市）。后人称司马睿为晋元帝为了拉拢世家贵族，用王敦堂弟王导为当朝丞相，封王敦扬州刺史训练精兵良将。

当时一般老百姓讲：“王与马（司马氏），共天下。”首都建康位于长江下游，而王敦率军屯驻在长江上游，对京城产生了极大的威慑力。晋元帝任命刘隗和戴渊防范king, 王敦看透了心思，但又不敢直接带兵进犯国都，因为这样一来，他的反心就昭然若揭了。

想到这里，King Dun just prepare to clear the state of Liu Yu with a pretext. Liu Yu was an evil man who hid in the city walls like a fox or in the temple like a mouse. King Dun and his Long Shu planned to kill him.

Liu Yu was defeated and fled to Later Zhao, never returning to the south again. King Dun's power grew even more arrogant after this victory, but he eventually died of illness before he could do any more harm.

The story of King Dun is known as "Castle Fox and Temple Rat," which means hiding behind someone else's power and influence while causing trouble.