The world in 1237 AD — what happened that year

7 events the sources record for this year, grouped by region.

What happened

The Mongols attacked Baghdad and Erbil, fighting from the city to the citadel (partly damaged). (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 15012–15014)
The Caliph sent Arslan Tekin with three thousand cavalry as reinforcements; on hearing of their arrival the Mongols suddenly fled (…) (partly damaged). (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 15048–15050)
The Caliph declared holy war (jihad), had the citizens occupied with bows and weapons, and ordered the moat and walls of Baghdad repaired. (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 15051–15053)
Caliph al-Mustansir came out of the city, gathered the citizens and addressed them. As the Mongols were chased, many died, and captives and horses were recovered; the event took place on a Friday. (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 15084–15090)

Batu burned the capital of Bolgar in the autumn of 1237 (described as reduced to a handful of ash). (Karamzin, History of the Russian State 제3권 VIII장)
Solar eclipse on 3 August. (Novgorod First Chronicle litopys 기사 1237년)
The princes united, besieged Ryazan («ریازان»), took it in three days, and then took other cities as well; Kölgen was wounded (the line breaks at the next word «وفا…»). (Rashid al-Din, Jami' al-tawarikh (Compendium of Chronicles) 87460_djvu.txt 줄 5748–5750)