Editing 1237 (section)

== Events ==
<onlyinclude>

=== By place ===

==== Europe ====

* Summer &ndash; Emperor [[Frederick II, Holy Roman Emperor|Frederick II]] assembles an expeditionary force (some 15,000 men) to crush the rebellious [[Lombard League]]. He crosses the [[Alps]] to [[Verona]] – where he is joined by Lord [[Ezzelino III da Romano]], including troops from [[Brescia]], [[Vicenza]], [[Padua]] and [[Treviso]]. Frederick relies on his allies for support and in doing so, he provokes the opposition of earlier supporters, such as the [[House of Este]], which now sides with the Lombards.
* [[August 15]] &ndash; [[Battle of the Puig]]: Aragonese forces under [[Bernat Guillem de Montpeller]] defeat the Muslim army (some 12,000 men) of the [[Taifa of Valencia]] at [[El Puig]]. The Almohad forces are routed, and many of the soldiers are slain in the action. [[Zayyan ibn Mardanish]], Almohad ruler and governor of [[Valencia]], is forced to go into exile to [[Tunisia]], while offering the surrender of all castles from the [[Turia (river)|Turia River]] to [[Tortosa]] and [[Teruel]].
* [[November 27]] &ndash; [[Battle of Cortenuova]]: Frederick II defeats the forces of the Lombard League; about 5,000 Lombards are captured. Frederick makes a triumphal entry into the allied city of [[Cremona]] in the manner of an ancient [[Roman emperor]], with the captured ''[[carroccio]]'' (later sent to the commune of [[Rome]]), and an elephant. During the winter campaign, Frederick captures the [[Piedmont]]ese cities of [[Lodi, Lombardy|Lodi]], [[Novara]], [[Vercelli]], [[Chieri]], and [[Savona]].<ref>{{cite book|author=John Larner|title=Italy in the Age of Dante and Petrarch, 1216-1380|url=https://books.google.com/books?id=QRsZAQAAMAAJ|year=1980|publisher=Longman|isbn=978-0-582-48366-8|page=31}}</ref> 
* At the urging of King [[Louis IX of France]], [[Thomas, Count of Flanders|Thomas II]] marries [[Joan, Countess of Flanders|Joanna]], widow of [[Ferdinand, Count of Flanders|Ferdinand of Flanders]], and daughter of the late Latin Emperor [[Baldwin I, Latin Emperor|Baldwin I]]. Thomas becomes count of [[County of Flanders|Flanders]] (or ''[[Jure uxoris]]'').<ref>{{cite book |last1=Coss |first1=Peter R. |last2=Coss |first2=P. R. |last3=Lloyd |first3=Simon D. |title=Thirteenth Century England II: Proceedings of the Newcastle Upon Tyne Conference 1987 |date=1988 |publisher=Boydell & Brewer |isbn=9780851155135 |page=83 |url=https://books.google.com/books?id=mFhOA1a0jnkC&pg=PA83|language=en}}</ref>
* [[Livonian Crusade]]: The [[Livonian Brothers of the Sword]] are absorbed into the [[Teutonic Order]], as the autonomous [[Livonian Order]]. An Estonian rebellion begins on [[Saaremaa]] Island (located in the [[Baltic Sea]]).

==== England ====
* [[September 25]] &ndash; [[Treaty of York]]: King [[Henry III of England|Henry III]] signs an agreement with [[Alexander II of Scotland]] at [[York]]. Alexander subjects to Henry's sovereignty and renounces the Scottish claims to [[Northumberland]], [[Westmorland]] and [[Cumberland]]. This establishes the [[Anglo-Scottish border]] in a form with the future status of several feudal properties and marks the end of [[Kingdom of Scotland|Scotland]]'s attempts to extend its frontier southward.<ref>Hywel Williams (2005). ''Cassell's Chronology of World History'', p. 139. {{ISBN|0-304-35730-8}}.</ref>

==== Mongol Empire ====
* Autumn &ndash; [[Mongol invasion of Kievan Rus']]: The Mongol army commanded by [[Batu Khan]] and [[Subutai]], invades the [[Principality of Ryazan]] (with representatives of all four [[khanate]]s leading some 100,000 Mongol, [[Turkic peoples|Turks]] and [[History of Iran|Persian]] forces into [[Europe]]). In December, Batu Khan sends envoys to the Rus' court of Grand Prince [[Yuri of Ryazan|Yuri Igorevich]] and demands the submission of the capital [[Ryazan]].
* [[Battle of Voronezh River]]: Grand Prince [[Yuri II of Vladimir]] supported by border princes of [[Ryazan]], [[Murom]], and [[Pronsky District|Pronsk]] gathers his forces and make a stand on the [[Voronezh (river)|Voronezh River]], waiting for reinforcements from [[Vladimir, Russia|Vladimir]]. The Mongols under Batu Khan overrun the Rus' forces, who are scattered. Yuri retreats to Ryazan, while some troops withdraw to [[Kolomna]] and join the army of [[Vladimir-Suzdal]].
* [[December 16]]&ndash;[[December 21|21]] &ndash; [[Siege of Ryazan]]: The Mongols under Batu Khan lay siege to Ryazan. The townspeople repel the first Mongol attacks but after 5 days the city walls are breached by Chinese catapults. On [[December 21]], the Mongols storm the walls and plunder the capital, killing Yuri Igorevich and all inhabitants. Yuri II of Vladimir stands by and does nothing to intervene while Ryazan burns.
* December &ndash; [[Siege of Kolomna]]: Rus' forces under Yuri II of Vladimir are besieged and annihilated at Kolomna by the Mongols. Yuri barely escapes to [[Yaroslavl]]. The defenceless capital of Vladimir is taken after just 2 days. Yuri's wife Agatha (sister of [[Michael of Chernigov]]) and all his family die in Vladimir when a church where they have sought refuge from the fire collapses.

==== Levant ====
* Spring &ndash; [[Al-Ashraf Musa, Emir of Damascus|Al-Ashraf Musa]], Ayyubid ruler of [[Damascus]], assembles his allies and secures his active support of [[Kayqubad I]], Sejuk ruler of the [[Sultanate of Rum]]. A civil war seems inevitable when Kayqubad is poisoned during a feast at [[Kayseri]], on [[May 31]].<ref>Steven Runciman (1952). ''A History of The Crusades. Vol III: The Kingdom of Acre'', p. 176. {{ISBN|978-0-241-29877-0}}.</ref> Meanwhile, the Seljuks strengthen the fortresses in the eastern provinces against the Mongols.
* [[August 27]] &ndash; Al-Ashraf becomes dangerously ill and dies after an 8-year reign. He is succeeded by his brother [[As-Salih Ismail, Emir of Damascus|As-Salih Ismail]] – who defends Damascus against his elder brother [[Al-Kamil]], Ayyubid ruler of [[Egypt in the Middle Ages|Egypt]]. In October, Ismail has the suburbs burnt to prevent the Egyptian forces from shelter.<ref>Burns, Ross (2005). ''Damascus: A History'', p. 186. Routledge. {{ISBN|978-0-415-27105-9}}.</ref>

=== By topic ===

==== Cities and Towns ====
In [[Kingdom of England|England]] the central tower of [[Lincoln Cathedral]] collapses.
* [[Cölln]], twin city of the later built [[Alt-Berlin]], is founded on the [[Fischerinsel]]. The town becomes a trade center, which is linked with [[Magdeburg]] and [[Frankfurt (Oder)|Frankfurt an der Oder]].
* [[Elbląg]] is founded by the Teutonic Order under Grand Master [[Hermann Balk|Hermann von Balk]]. He constructs a fortified stronghold on the banks of the [[Elbląg (river)|Elbląg River]] (modern [[Poland]]).</onlyinclude>