Cui Yan
However, Cao Pi's status as heir was not immediately made legal, and for years there were lingering doubts on whom Cao Cao intended to make heir. Cao Cao greatly favoured Cao Zhi (his third son with Lady Bian), who was known for his literary talents. Both Cao Pi and Cao Zhi were talented poets, but Cao Zhi was more highly regarded as a poet and speaker. By 215, the brothers appeared to be in harmony with each other, but each had his own group of supporters and close associates engaging the other side in clandestine rivalry. Initially, Cao Zhi's party appeared to be prevailing, and in 216 they were successful in falsely accusing two officials supporting Cao Pi – Cui Yan and Mao Jie. Cui Yan was executed, while Mao Jie was deposed. However, the situation shifted after Cao Cao received advice from his strategist Jia Xu, who concluded that changing the general rules of succession (primogeniture) would be disruptive – using Yuan Shao and Liu Biao as negative examples. Cao Pi was also fostering his image among the people and created the sense that Cao Zhi was wasteful and lacking actual talent in governance. In 217, Cao Cao, who had received the title of a vassal king – King of Wei () – from Emperor Xian (whom he still paid nominal allegiance to), finally declared Cao Pi as his heir apparent (). Cao Pi would remain as such until his father's death in 220.