Liaoyang (1029) — the same event in History of Liao and Goryeosa

History of Liao: At the Eastern Capital, Da Yanlin, Shangwen of the Shelijun army, imprisoned the governor Xiao Xiaoxian and founded the state of…

What each source says

History of Liao (Liaoshi) · AD 1029 · 東京遼陽府

At the Eastern Capital, Da Yanlin, Shangwen of the Shelijun army, imprisoned the governor Xiao Xiaoxian and founded the state of Xingliao (era Tianqing).

八月己丑,東京舍利軍詳穩大延琳囚留守駙馬都尉蕭孝先及南陽公主,殺戶部使韓紹勛、副使王嘉、四捷軍都指揮使蕭頗得,延琳遂僭位,號其國為興遼,年為天慶。
Location: 遼史 卷17 太平9年 8月

Goryeosa (History of Goryeo) · AD 1029 · 遼陽

Dae Yeon-rim, a seventh-generation descendant of Dae Jo-yeong, raises a revolt against the Khitan, names the state Heungryo and the era Cheonheung.

延琳渤海始祖大祚榮七代孫,叛契丹,國號興遼,建元天興。
Location: 世家 卷5 顯宗 七年

Place: 東京

Show on the map — open History of Liao (Liaoshi)