16 events the sources record for this year, grouped by region.
What happened
China (5)
Mongol troops pacified Fengxiang Prefecture; the two provincial commands abandoned Jingzhao and moved its people to Henan. (History of Jin (Jinshi), Annals 金史 卷017 哀宗 正大八年4月)
Hezhong Prefecture fell, and Caohuo E'ke, acting vice-commissioner of the Privy Council, died. (History of Jin (Jinshi), Annals 金史 卷017 哀宗 正大八年12月)
He took Fengxiang and attacked and captured the cities of Luoyang and Hezhong. (History of Yuan (Yuanshi), Annals 元史 卷2 太宗 1231年 2月)
In the eighth month the Mongol Tulei entered Dasan Pass with thirty thousand cavalry, broke Fengzhou and massacred Yangzhou; he came out at Wuxiu and finally besieged Xingyuan. (Xu Zizhi Tongjian (Continuation of the Comprehensive Mirror) 권165 八月 단락165.31.0)
Korean Peninsula (7)
Because Goryeo had killed envoys, Salitai was sent to take more than forty towns, and the Goryeo king sent his younger brother to beg submission. (History of Yuan (Yuanshi), Annals 元史 卷2 太宗 1231年)
Mongol troops besiege Gwiju Fortress but withdraw without victory (first invasion). (Goryeosa (History of Goryeo) 世家 卷23 高宗 十八年)
When the Mongols besiege Yongju, the garrison asks for surrender, and the magistrate Wi So is taken prisoner. (Goryeosa (History of Goryeo) 世家 卷23 高宗 十八年)
At Pyeongju the Mongols kill the magistrate, massacre the walled town, and burn every house. (Goryeosa (History of Goryeo) 世家 卷23 高宗 十八年)
1231: Mongol forces destroy over 200 kan of Gwiju's walls and attack with 28 catapults, putting soldiers of surrendered fortresses in front; the residents fight to the death and win a great victory (Goryeosa Jeolyo (Essentials of Goryeo History) 권16 高宗 十八年)
The Mongols attack Gwiju again with cannon carts; Bak Seo answers with catapults. He refuses Salietai's call to surrender and smashes the ladder-cart assault with the Daeu catapult (Goryeosa Jeolyo (Essentials of Goryeo History) 권16 高宗 十八年)
West Asia (3)
The Mongol army reached a city on the bank of the Mören (Yellow) River and besieged it; after forty days, its people asked for (…) (OCR-damaged; the city name «…ینقین» is illegible). (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 4803–4805)
Tolui went to Tibet («تبت»), passed through the Kitai region where the «Hulan» (meaning red people) live, and came before the great army of Altan Kan. (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 13312–13318)
Eastern Europe & Russia (1)
A great fire in the Slavensky district (the fire also burned on the water of the Volkhov). (Novgorod First Chronicle litopys 기사 1231년)