Pyongyang (1269) — the same event in History of Yuan and Goryeosa Jeolyo

History of Yuan: Goryeo's Commander-in-Chief Choi Tan and others, citing Im Yeon's rebellion, led over fifty fortresses of Seogyeong to surrender…

What each source says

History of Yuan (Yuanshi), Annals · AD 1269 · 平壤

Goryeo's Commander-in-Chief Choi Tan and others, citing Im Yeon's rebellion, led over fifty fortresses of Seogyeong to surrender.

十一月癸卯,高麗都統領崔坦等,以林衍作亂,挈西京五十餘城來附。
Location: 元史 卷6 世祖 1269年 11月

Goryeosa Jeolyo (Essentials of Goryeo History) · AD 1269 · 平壤

1269: Choe Tan kills Seogyeong governor Choe Nyeon, judge Yu Chan and the magistrates of Yongju, Yeongju, Cheolju and Seonju, and the officials of the remaining fortresses all fall to the enemy; he defects to the Mongols

○崔坦殺西京留守崔年判官柳粲司錄曹英紱龍州守庾希亮靈州守睦德昌鐵州守金鼎和宣州守金義慈州守金潤。
Location: 권18 元宗順孝大王 十年

Where the sources differ

A and B are two of the sources listed above.

On what pointSource ASource BWhat differs (in Korean)
WhoHistory of Yuan (Yuanshi), AnnalsGoryeosa Jeolyo (Essentials of Goryeo History)a는 최탄이 50여 성을 이끌고 귀부했다고 적고, b는 서경유수 최년 등을 죽이고 성들이 넘어갔다고 적음

Place: 平壤

Show on the map — open History of Yuan (Yuanshi), Annals