Pingcheng (471) — the same event in Book of Wei and Zizhi Tongjian

Book of Wei: Emperor Xianwen abdicated in favor of Crown Prince Hong, became Taishang Huangdi, and moved to the Chongguang Palace.; Book of Wei…

What each source says

Book of Wei (Weishu), Imperial Annals · AD 471 · 平城

Emperor Xianwen abdicated in favor of Crown Prince Hong, became Taishang Huangdi, and moved to the Chongguang Palace.

己酉,太上皇帝徙御崇光宮,採椽不斵,土階而已。
Location: 魏書卷6·皇興五年

Book of Wei (Weishu), Imperial Annals · AD 471 · 平城

Emperor Xiaowen, Tuoba Hong, ascended the throne in the Taihua Hall.

五年秋八月丙午,即皇帝位於太華前殿,大赦,改元延興元年。
Location: 魏書卷7上·延興元年

Zizhi Tongjian (Comprehensive Mirror) · AD 471 · 平城

Emperor Xianwen of Northern Wei yields the throne; Emperor Xiaowen ascends at Pingcheng with reign title Yanxing (August).

丙午,高祖即皇帝位,大赦,改元延興
Location: 卷133

Place: 平城

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