1231

Events

Emperor Frederick II promulgates the Constitutions of Melfi, a collection of laws for Sicily, as well as the Edict of Salerno, regulating the exercise of medicine and separating the professions of physician and apothecary, and requiring medical schools to practice dissection.Reconquista:
* Castillian forces under King Ferdinand III re-conquer the city of Quesada.
* Battle of Jerez: Ferdinand III defeats Emir Ibn Hud of the Taifa of Murcia.
Peter des Roches, Bishop of Winchester, negotiates a 3-year truce between England and France.

Spring - Hubert de Burgh becomes a powerful lord in the Welsh Marches, controlling the castles at Cardigan and Carmarthen. He begins to threaten the local Welsh leaders, Llywelyn the Great launches a campaign against Norman lordship in Wales.
August 13 - King Henry III orders the sheriffs of Hampshire, Dorsetshire and Wiltshire to give Simon de Montfort the possession of the lands of his father, Simon de Montfort the elder.
December - Henry III ends his Welsh campaign and makes peace with Llywelyn the Great.
The University of Cambridge is recognised by a writ of authority over its townspeople from Henry III.

Autumn - Frederick II appoints Marshal Richard Filangieri as his imperial legate, and sends an expeditionary army of mostly Lombards for the defense of Jerusalem. He gathers some 600 knights, 100 "sergeants-at-arms", 700 armed infantrymen, and 3,000 marines. The army is supported by 32 war-galleys.
War of the Lombards: Richard Filangieri sails for Beirut, where the town is handed over to him. He occupies Sidon and Tyre – while other Lombard forces appear before Acre. At Acre, Filangieri summons a meeting of the High Court and shows letters from Frederick II appointing him as ambassador.

April 9 - A huge fire breaks out at night in the southeast of Hangzhou during the Song dynasty. Fighting the flames is difficult due to limited visibility. When the fires are extinguished, it is discovered that an entire district of the city has been consumed by the flames.

August - Ögedei Khan orders the invasion of Korea. A Mongol army crosses the Yalu River and quickly secures the surrender of the border town of Uiju. The Mongols are joined by Hong Pok-wŏn, a Goryeo general, who takes their side with his subordinates numbering some 1500 families.
Siege of Kuju: Mongol forces besiege the city of Kuju. They deploy assault teams who man siege towers and scale ladders. Despite the fact the Goryeo army is heavily outnumbered, the garrison refuses to surrender.

April 13 - Pope Gregory IX issues Parens scientiarum. The bull assures the independence and self-governance of the University of Paris.