In 249, the Grand Commandant Wang Ling plotted with his maternal nephew Linghu Yu (令狐愚), the Inspector of Yan Province, to overthrow the Wei emperor Cao Fang (Cao Rui's successor) and replace him with Cao Biao, whom they perceive to be intelligent and courageous.(魏畧曰：愚聞楚王彪有智勇。) Weilue annotation in Sanguozhi vol. 28. They also planned to establish the new imperial capital in Xuchang. In late September or October 249, Linghu Yu sent his subordinate Zhang Shi (張式) to contact Cao Biao and tell him that there were two popular sayings circulating in Dong Commandery (東郡; around present-day Puyang County, Henan): Both sayings hinted that Cao Biao should become the emperor. Zhang Shi also told Cao Biao, "His Excellency (Linghu Yu) sends Your Highness his greetings. There is great uncertainty in this world. We hope that Your Highness will love yourself." Cao Biao caught the hint and replied, "I thank His Excellency for his generosity and support."(楚王小字朱虎，故愚與王淩陰謀立楚王。乃先使人通意於王，言「使君謝王，天下事不可知，願王自愛」！彪亦陰知其意，荅言「謝使君，知厚意也。」) Weilue annotation in Sanguozhi vol. 28. In December 249 or January 250, Linghu Yu sent Zhang Shi to remind Cao Biao again, but he died of illness before Zhang Shi returned.([王]淩、愚密協計，謂齊王不任天位，楚王彪長而才，欲迎立彪都許昌。嘉平元年九月，愚遣將張式至白馬，與彪相問往來。 ... 其十一月，愚復遣式詣彪，未還，會愚病死。) Sanguozhi vol. 28.(漢晉春秋曰：淩、愚謀，以帝幼制於彊臣，不堪為主，楚王彪長而才，欲迎立之，以興曹氏。) Han Jin Chunqiu annotation in Sanguozhi vol. 28.(嘉平元年，兖州刺史令狐愚與太尉王淩謀迎彪都許昌。) Sanguozhi vol. 20.
