10 events the sources record for this year, grouped by region.
What happened
China (1)
Princes and generals from the west and east held another great assembly at Kute Aral and enthroned Möngke. (History of Yuan (Yuanshi), Annals 元史 卷3 憲宗 1251年 6月)
Korean Peninsula (3)
Mongol envoy Go-i says the northwest border has already been badly ravaged, so rather than return to the old capital, rely on the rivers and defend oneself. (Goryeosa (History of Goryeo) 世家 卷24 高宗 三十八年)
January 1251: the king entertains the Mongol envoy Honggoi at Jepogung. The envoy says the north has already been destroyed and a return to the old capital is impossible, so they should defend by relying on the river, and that he will go back and report (Goryeosa Jeolyo (Essentials of Goryeo History) 권17 高宗 三十八年)
Möngke entrusted the eastern (Kitai) region to Yalavach (Mahmud Yalavach), and the Uighur, Fergana, and Khwarazm lands to Mas'ud Beg, a division of administration. (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 17327–17331)