Cao Gan was a son of Cao Cao, a warlord who rose to prominence towards the end of the Han dynasty and laid the foundation for the Cao Wei state. His birth mother was Lady Chen, a concubine of Cao Cao, but he was raised by Lady Wang, another of Cao Cao's concubines, because Lady Chen died early. In 215, Cao Gan was enfeoffed as the "Marquis of Gaoping Village" by Emperor Xian, the figurehead emperor of the Han dynasty. In 217, his title was first changed to "Marquis of Lai Village" and then to "Marquis of Hongnong" within the same year. When Cao Cao was critically ill in early 220, he told his heir apparentCao Pi, "This boy was only three years old when his mother died. Now, he's going to lose his father too when he's just five years old. Please take good care of him." Cao Pi followed his father's dying wish and treated Cao Gan and his other half-brothers kindly. The young Cao Gan often called Cao Pi "aweng" but Cao Pi corrected him, "I am your elder brother." Cao Pi was often moved to tears when he saw how Cao Gan looked up to him like a father. 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. In 222, he promoted Cao Gan from a duke to a prince under the title "Prince of Hejian". Cao Gan's title was later changed to "Prince of Lecheng" in 224, and then to "Prince of Julu" in 226. In 232, Cao Pi's successor, Cao Rui, changed Cao Gan's title to "Prince of Zhao". In 234, someone reported Cao Gan to the imperial court for violating imperial protocol by privately hosting guests without authorisation. Although Cao Rui did not punish Cao Gan for the infringement, he issued an imperial decree to reprimand Cao Gan for his conduct. Throughout the later reign of Cao Rui to the reigns of the subsequent Wei emperors, the number of taxable households in Cao Gan's princedom increased until it reached 5,000. Cao Gan died on 14 September 261 during the reign of Cao Huan, the last Wei emperor.
