Chang'an (600) — the same event in History of the Northern Dynasties and Book of Sui

History of the Northern Dynasties: Crown Prince Yang Yong and his sons were demoted to commoners; in the eleventh month Yang Guang was made crown…

What each source says

History of the Northern Dynasties (Beishi), Annals · AD 600

Crown Prince Yang Yong and his sons were demoted to commoners; in the eleventh month Yang Guang was made crown prince.

廢皇太子勇及其諸子。並為庶人
Location: 北史 卷11 開皇20年

Book of Sui (Suishu), Imperial Annals · AD 600 · 長安

Crown Prince Yang Yong and his sons were deposed and made commoners.

皇太子勇及諸子並廢為庶人
Location: 隋書 卷002 帝紀 開皇20年10月

Place: 長安

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