During the Northern Wei Dynasty, the practice of retired emperorship was practiced as a means to stabilize imperial successions; however, it is also closely simultaneous with organizations attempting to establish a primogenital type of succession over a prior potential institution of parallel succession.
Before the Northern Wei established their rule in China, the ruling Toba house was a nomad confederate chieftaincy, with the reins of power passing from brother to brother. There were also cases of uncle to nephew and nephew to uncle. However, once the Northern Wei Dynasty established their rule, they “successfully and rapidly engineered a switch from a horizontal, fraternal mode of political succession to a vertical, primogenital mode of succession. Generally speaking, the emperor's eldest son inherited the throne”.
For example, in 471 CE, emperor Xianzu retired from emperorship. At 16 years old, he proclaimed a four year old boy his heir, the future Xiaowendi, emperor. “Initially, during the course of a court conference called to discuss the issue, Xianzu offered the throne to his eldest paternal uncle, but retracted the offer in the face of strong court opposition”.
Xianzu was 11 years old when he became emperor in 467, the previous two years were a time of power struggles which saw him taking the throne. In 465 -647, his father’s first cousin, Toba Daofu, had unsuccessfully revolted and, according to one scholar, this traumatized the young emperor’s early reign. “In sum, Xianzu's retirement was an effort to insure the legitimacy of his young son upon the throne. The retirement would also serve to guarantee that the degree of accumulated court support for the young emperor would be sufficient to withstand future threats to the throne in the eventuality of Xianzu's unforeseen demise”.
The retirement of the emperor generally meant his removal to a separate palace complex buildings and then his heir was formally proclaimed emperor. However, it was more of a co-regency rather than complete retirement – in many cases the retired emperor would still manage all state affairs until he died. Until the retired emperor died the boy-emperor (all were under the age of 10 at their ascension) was required to visit him at his court at least once a month. As one scholar states, “Xianzu's institution of the Retired Emperorship was a bridge between the non-formal, familialistic power arrangements of Gaozong, and the formal institutional experimentation of the emperor Xiaowendi”.
Bibliography:
Eisenberg, Andrew (1991) Retired Emperorship in Medieval China: The Northern Wei, T'oung Pao, BRILL.