Cao Huan
In 263, during the reign of Cao Huan, Sima Zhou was appointed as General of the Right (右將軍) and Inspector (刺史) of Yan Province. A year later, after Sima Zhao restored the five-rank nobility system, which had previously been abolished, Sima Zhou was enfeoffed as the Count of Nanpi (南皮伯). He was also reassigned to be General Who Attacks Barbarians (征虜將軍) and granted imperial authority.