[4] In 215, Cao Gan was enfeoffed as the "Marquis of Gaoping Village" (高平亭侯) by Emperor Xian, the figurehead emperor of the Han dynasty.
The young Cao Gan often called Cao Pi "aweng" (阿翁; an affectionate way of addressing one's father, grandfather or an older man) but Cao Pi corrected him, "I am your elder brother."
[1][7] In 220, Cao Pi usurped the throne from Emperor Xian, ended the Han dynasty, and established the Cao Wei state with himself as the new emperor.
A year later, he enfeoffed his half-brother Cao Gan as the Duke of Yan (燕公).
In 234, someone reported Cao Gan to the imperial court for violating imperial protocol by privately hosting guests without authorisation.