1250s

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Millennium
2nd millennium
Centuries
12th century 13th century 14th century
Decades
1230s 1240s 1250s 1260s 1270s
Years
1250 1251 1252 1253 1254 1255 1256 1257 1258 1259
Categories
Births Deaths By country Establishments Disestablishments
v t e

The 1250s decade ran from January 1, 1250, to December 31, 1259.

• The world population is estimated at between 400 and 416 million individuals.
• World climate transitions from the Medieval Warm Period to the Little Ice Age.^[1]

• February 2 – King Erik Eriksson of Sweden dies. The ten-year-old Valdemar, the eldest son of Birger Jarl, is elected King of Sweden, and becomes the first king from the House of Bjälbo.
• October 12 – A great storm shifts the mouth of the River Rother in England 12 miles (20 km) to the west; a battering series of strong storms significantly alters other coastal geography around Romney Marsh.
• December 13 – Emperor Frederick II dies, beginning the 23-year-long "Great Interregnum". Frederick is the last Holy Roman Emperor of the Hohenstaufen dynasty; after the interregnum, the empire passes to the Habsburgs.
• The Lombard League dissolves upon the death of its member states' nemesis, Frederick II, Holy Roman Emperor.
• King Afonso III (the Boulonnais) captures the Algarve from the Moors, thus completing the expulsion of the Moors from Portugal.
• Albertus Magnus isolates the element arsenic, as the 8th discovered metal. He also first uses the word "oriole" to describe a type of bird (most likely the golden oriole).
• The Rialto Bridge in Venice (in modern-day Italy) is converted from a pontoon bridge to a permanent, raised wooden structure.
• The Ponts Couverts fortified bridges of Strasbourg (in modern-day France) are completed.
• Vincent of Beauvais completes his proto-encyclopedic work Speculum Maius ("Greater mirror").
• The first of the Parlements of Ancien Régime France is established.
• Villard de Honnecourt draws the first known image of a sawmill.
• The first usage is made of the English word "cuckold", according to the Oxford English Dictionary.
• Medieval music: The Notre Dame school of polyphony ends.

• July 9 – The Qaymariyya tribe engineers a coup d'état to hand over Damascus to An-Nasir Yusuf. The garrison in the citadel surrenders later to him.^[2]
• A kurultai is called by Batu Khan in Siberia as part of maneuverings which will elect Möngke Khan as khan of the Mongol Empire in 1251.
• Starting in this year and ending in 1275, the Muslim Shougeng Pu, likely a Persian or an Arab, serves as the Commissioner of Merchant Shipping for the Song dynasty Chinese seaport at Quanzhou, due to his effort in defeating pirates.^[3]

• April 8 – Battle of Fariskur: Louis IX (the Saint) is captured by Baibars' Mamluk army while he is in Egypt conducting the Seventh Crusade; he later has to ransom himself.
• April 30 – King Louis IX (the Saint) is released by his Egyptian captors after paying a ransom of one million dinars and turning over the city of Damietta.
• May 2 – Al-Muazzam Turanshah, Ayyubid ruler of Egypt, is murdered, ending effective Ayyubid Dynasty rule in the country. He is briefly succeeded by his widow, Sultana Shajar al-Durr.^[4]
• July 21 – Aybak becomes ruler of Egypt, beginning the Bahri Dynasty of the Mamluk Sultanate. After 5 days he stands down and the six-year-old Al-Ashraf Musa is nominally proclaimed sultan.^[4]
• The Welayta state is founded in modern-day Ethiopia.
• In Tunis, a popular rebellion against newly arrived, wealthy and influential Andalusian refugees breaks out, and is violently put down.^[5]
• The Hafsid caliph al-Mustansir enforces laws of ghiyar, or differentiation for non-Muslims. As such, Jews have to wear a distinguishing badge (shikla) which Tunisian Jews will have to wear into the nineteenth century.^[6][7]

• Samoa frees itself from Tongan rule, which begins the Malietoa dynasty in Samoa (approximate date).

• The Flemish town of Douai emits the first recorded redeemable annuities in medieval Europe, confirming a trend of consolidation of local public debt started in 1218, in Rheims.^[8]
• The Sienese bankers belonging to the firm known as the Gran Tavola, under the steering of the Bonsignori Brothers, become the main financiers of the Papacy.^[9]

• April – The first Shepherds' Crusade, a domestic French uprising in response to events in Egypt during the Seventh Crusade, occurs.^[10][11]
• May – English governor Simon de Montfort suppresses a revolt in Gascony.^[12]
• December 26 – King Alexander III of Scotland marries Margaret, daughter of King Henry III of England, precipitating a power struggle between the two monarchs.^[13][14]
• Andrew de Longjumeau, dispatched two years earlier by King Louis IX of France as an ambassador to the Mongols, meets the king in Palestine, with reports from the Mongols and Tartary; his mission is considered a failure.^[15][16]
• Mindaugas of Lithuania is baptized, in prelude to his crowning as King of Lithuania in 1253.^[17]
• Alexander Nevsky signs the first peace treaty between Kievan Rus' and Norway.^[18][19][20]
• King Conrad IV of Germany invades Italy, but fails to subdue the supporters of Pope Innocent IV.^[21][22]
• Ottokar II of Bohemia, later to become King of Bohemia, is elected Duke of Austria.^[23][24]
• The earliest known manuscript of The Proverbs of Alfred, a collection of sayings of England's Alfred the Great, is written.^[25]

• April 21 – City of Launggyet in Arakan (modern-day Burma) is founded according to some sources.^[26]
• July 1 – Möngke Khan is elected as the fourth great Khan of the Mongol Empire.^[27][28]
• The carving of the Tripitaka Koreana, a collection of Buddhist scriptures recorded on some 81,000 wooden blocks, is completed.^[29][30]

• April 6 – Saint Peter of Verona is assassinated by Carino of Balsamo.^[31][32]
• May 15 – Pope Innocent IV issues the papal bull Ad exstirpanda, which authorizes the torture of heretics in the Medieval Inquisition. Torture quickly gains widespread usage across Catholic Europe.^[33][34]
• June 1 – Alfonso X is proclaimed king of Castile and León.^[35]
• July – The settlement of Stockholm in Sweden is founded, by Birger Jarl.^[36][37]
• December 25 – Christopher I of Denmark is crowned King of Denmark, in the Lund Cathedral.^[38][39]
• The Polish land of Lebus is incorporated into the German state of Brandenburg, marking the start of Brandenburg's expansion into previously Polish areas (Neumark).^[40]
• The Lithuanian city of Klaipėda (Memel) is founded by the Teutonic Knights.^[41][42]
• The town and monastery of Orval Abbey in Belgium burn to the ground; rebuilding takes 100 years.^[43]
• Thomas Aquinas travels to the University of Paris, to begin his studies there for a master's degree.^[44][45]
• In astronomy, work begins on the recording of the Alfonsine tables.^[46]

• The classic Japanese text Jikkunsho is completed.^[47][48]
• The Chinese era Chunyou ends.^[49]
• The Mongols take the westernmost province of the Song dynasty empire.^[50]

• January 18 – King Henry I of Cyprus ("the Fat") dies and is succeeded by his son Hugh II, who is only a few months old. His mother, Queen Plaisance of Antioch, claims the regency of Cyprus and the titular regency of Jerusalem. The High Court of Cyprus confirms her position, but the barons of Outremer require her attendance in person before they will recognize her. John of Ibelin, count of Jaffa, remains as bailli, and Plaisance contemplates marrying John's youthful son Balian. Meanwhile, King Louis IX of France ("the Saint"), still staying at Acre, continues to administer the government.^[51]
• Summer – The Kingdom of Galicia–Volhynia becomes a vassal state to the expanding Mongol Empire. Prince Daniel of Galicia is crowned "Rex Rusiae" and becomes officially an Orthodox subject of the Papal States.
• July 4 – William II, count of Holland, defeats the Flemish forces under Guy of Dampierre at Westkapelle. He forced him and his mother, Margaret II, to respect the division of Flanders and Hainaut.
• July 6 – Mindaugas and his wife Morta are crowned as king and queen of Lithuania, ruling between 300,000 and 400,000 subjects.^[52]
• October 10 – German imperial forces under King Conrad IV suppress the Sicilian rebellion and recapture Naples.

• August 6 – King Henry III leads an expedition to Gascony, to repel a rumoured invasion from Castile.^[53] Meanwhile, Simon de Montfort returns from Gascony where he allies himself with the barons who oppose Henry.
• Henry III meets with the nobles and church leaders to reaffirm the validity of Magna Carta in exchange for taxation.^[54]

• April – An-Nasir Yusuf, Ayyubid ruler of Damascus, cedes Palestine, together with Jerusalem, Nablus and the coastline of Al-Sham to Aybak, Mamluk sultan of Egypt.

• April 28 – Nichiren, Japanese Buddhist monk, declares his intent to preach the Lotus Sutra and Namu Myōhō Renge Kyō as the true Buddhism, thus founding Nichiren Buddhism.
• May – Louis IX of France ("the Saint") dispatches William of Rubruck from Constantinople on a missionary journey to Karakorum to seek an alliance against Syrian and Egyptian Muslims.^[55]
• Mongol forces under Hulagu Khan begin a campaign against the Nizari Ismaili State. An advance guard (12,000 men) under Kitbuqa captures several fortresses in Quhistan.
• Mongol forces under Kublai Khan conquer the Dali Kingdom (modern-day Yunnan). The population migrates to Siam (modern Thailand).
• Kublai Khan introduces the baisha xiyue song and dance suite to the music of Yunnan.

• Matthew Paris, English Benedictine chronicler, completes the major part of his Chronica Majora, a chronicle of English history.

• October – Pope Innocent IV returns to Rome, after being deposed for 9 years by former Emperor Frederick II, whose clash forms an important chapter in the conflict between the Papal States and the Holy Roman Empire.
• Innocent IV offers the crown of Sicily, which he controls, to Richard of Cornwall and Charles of Anjou, both of whom refuse, and later to the 8-year-old Edmund, son of Henry III of England.
• The upper Basilica of Saint Francis of Assisi, the earliest important structure of Italian Gothic architecture, is completed in Assisi.
• Sligo Abbey, a Dominican monastery, is founded by Maurice FitzGerald, Norman chief governor of Ireland.

• Battle of Adrianople: Byzantine forces under Emperor Theodore II (Laskaris) defeat the invading Bulgarians near Adrianople. The young and inexperienced Tsar Michael II Asen (also mentioned Michael I Asen) is caught by surprise and the Bulgarians suffer heavy losses. Michael is wounded during his hasty retreat through the forest.^[56]

• May 21 – King Conrad IV, son of the late Emperor Frederick II, dies of malaria at Lavello (southern Italy). With Conrad's death a interregnum begins, during which no ruler manages to gain undisputed control of Germany. The 22-year-old Manfred, half-brother of Conrad, refuses to surrender Sicily to Pope Innocent IV, and accepts the regency on behalf of Conrad's 2-year-old son Conradin (the Younger).
• November 2 – German forces under Manfred start an anti-papal revolt against Innocent IV and seize Lucera in the Tavoliere Plains. He defeats the papal army at Foggia and gains the loyalty of Apulia, on December 2.^[57]
• King Afonso III (the Boulonnais) holds the first session of the Cortes (Portugal's general assembly composed of nobles, members of the middle class and representatives from all municipalities), in Leiria.
• William II, anti-king of Germany, holds a diet (princely convention) at Worms, in which the German cities are represented for the first time. He give orders to build strong castles in Heemskerk and Haarlem.
• Doge Reniero Zeno sends the Horses of Saint Mark, looted from Constantinople during the Fourth Crusade, to Venice, where they are installed on the terrace of the façade of St. Mark's Basilica.

• King Henry III grants his eldest son Edward (the Lord Edward) areas of land including crown lands in Wales, Ireland, the Channel Islands and Gascony. He is also given the cities of Bristol, Stamford and Grantham. The reason for these concessions is to give Edward experience of governing lands of his own before becoming a king. Edward is granted the Three Castles in Wales, Skenfrith Castle, White Castle and Grosmont Castle.^[58]
• Summer – Edward (the Lord Edward) travels from Portsmouth with his mother, Queen Eleanor of Provence, and Boniface of Savoy, archbishop of Canterbury, to marry the 13-year-old Eleanor of Castile. She is the half-sister of King Alfonso X (the Wise). In August, they arrive in Burgos, capital of Castile, where the marriage is due to take place.
• November 1 – Edward marries Eleanor of Castile in the Cistercian monastery Las Huelgas at Burgos. Henry III has demanded the marriage, in exchange for ending the war with half-brother Alfonso X.

• February 21 – King Louis IX (the Saint) signs a multi-year truce with An-Nasir Yusuf, Ayyubid ruler of Damascus, who is well aware of a Mongol threat and has no wish for war with the Crusader States.
• April 24 – Louis IX and his family sails from Acre to France. His boat is nearly wrecked off the coast of Cyprus and later nearly destroyed by fire. In July, the royal party arrives at Hyères in Provence.^[59]

• January 4 – William of Rubruck, Flemish missionary and explorer, is received courteously with an embassy at Karakorum. He is given an audience with Möngke Khan, who is loaded with gifts and letters from Louis IX.^[60]

• June 12 – The Dutch city of Alkmaar obtains city rights from William II, anti-king of Germany.^[61]
• The Danish city of Copenhagen receives its city charter from Bishop Jacob Erlandsen.

• The Rhenish League, a confederation of trading cities, is established in the Rhineland, Western Germany. The league (or Städtebund) comprises 59 cities.

• The Japanese classic text Kokon Chomonjū is completed during the Kamakura Period under the reign of the 11-year-old Emperor Go-Fukakusa.

• As part of an offensive against usury in north-western Europe, Innocent IV relieves the city of Beauvais from its obligations to its creditors.^[62]

• December 7 – Innocent IV dies after a pontificate of 11-year. He is succeeded by Alexander IV as the 181st pope of the Catholic Church.
• The construction of the Cathedral of Saint Martin is initiated by Henry I van Vianden, bishop of Utrecht.
• The Catholic dogma of purgatory is clarified and named by the Catholic Church (approximate date).

• February 25 – Battle of Montebruno: Guelph forces under Thomas II of Savoy invade the Ghibelline territory of Asti (located in the Piedmont region), but he is defeated by the Astigiani army, led by William VII, at Garzigliana (Northern Italy). Thomas retreats and takes refuge in Turin; however, he is later captured by the Ghibellines.
• May – William of Rubruck from Constantinople returns to Cyprus from his missionary journey to convert the Mongols of central and eastern Asia, his efforts have been unsuccessful.
• Emperor Theodore II (Laskaris), who is in exile in the Empire of Nicaea, conducts a military campaign to recover Thrace from the Bulgarians.
• King Afonso III (the Boulonnais) moves his residence and royal court from Lisbon to Coimbra, which becomes the capital of Portugal.
• The Teutonic Knights in Prussia found Königsberg (modern-day Kaliningrad) and name it in honour of King Ottokar II of Bohemia.
• The lands of the House of Nassau are divided between the brothers Walram II and Otto I, not to be reunited until 1806.

• June – Battle of Bryn Derwin: Llywelyn ap Gruffudd defeats his two brothers Dafydd ap Gruffydd and Owain Goch ap Gruffydd, to become sole ruler of northern Wales. Dafydd and Owain are both imprisoned.^[53]
• August – Following the death of Little Saint Hugh, in an instance of blood libel, eighteen Jews of Lincoln, are tortured and executed by royal command on suspicion of being involved in the boy's murder.^[53]
• A survey of royal privileges is conducted, which is included in the Hundred Rolls, a census seen as a follow-up to the Domesday Book (completed in 1086). The Hundred Rolls is later completed with two larger surveys, in 1274/75 and 1279/80.^[63]

• The Gothic cathedral at Bourges in central France, is completed (it will become a UNESCO World Heritage Site).

• The town of Banská Bystrica (located in central Slovakia) is granted municipal privileges by King Béla IV of Hungary.

• Orlando Bonsignori, an Italian minor merchant, forms a consortium called the Gran Tavola ("Great Table"), which becomes the most powerful bank in western Europe. He becomes the exclusive banker for the deposits of the income of the Papal States.^[64]

• Spring – Mongol forces (some 80,000 men), under Hulagu Khan, cross the Oxus River, and begin their campaign to destroy the remaining Muslim states in southwestern Asia – with the first objectives being the Nizari Ismaili strongholds and Baghdad, the capital of the Abbasid Caliphate. The roads across Turkestan and Persia are repaired, and bridges built. Carts are requisitioned to bring siege machines from China.^[65]
• October – Mongol forces led by Baiju Noyan (operating under Hulagu Khan's command) win a victory over Kaykaus II, Seljuk ruler of the Sultanate of Rum, and capture Anatolia. Kaykaus flees to the Byzantine court where he seeks refuge at Constantinople. The Empire of Trebizond fearing a potential punitive Mongol expedition, becomes a vassal state and is forced to pay a tribute tax every year in gold and silk.^[66]
• November 8–23 – Siege of Maymun-Diz: Mongol forces under Hulagu Khan successfully besiege the mountain castle of Maymun-Diz. Hulagu encircles the fortress and begins a bombardment for three days by mangonels from a nearby hilltop. On November 19, Nizari Isma'ili imam Rukn al-Din Khurshah surrenders, but a small part of the garrison refuses and fights a last stand, until they are killed after three days.^[67]
• December 15 – Mongol forces under Hulagu Khan capture and dismantle Alamut Castle (near the Masoudabad region) after the surrender of the Nizari Ismaili leaders. Hulagu founds the Ilkhanate dynasty of Persia, which becomes one of the four main divisions of the Mongol Empire. The Nizari Ismaili government is disestablished, some of them migrate to Afghanistan, Badakhshan and Sindh (modern Pakistan).

• War of the Euboeote Succession: Achaean forces under William II of Villehardouin attempt to gain control of the island of Euboea, which is resisted by the local Lombard barons (or "triarchs") with the aid of the Republic of Venice. William launches devastating raids in Euboea. Guy I de la Roche, the "Great Lord" of Athens and Thebes, enters the war against William, along with other barons of Central Greece.^[68]
• 30 July – The Venetian Marsilio Zorzi recaptures Curzola in Dalmatia, and re-establishes himself as Count of Curzola and Mèleda.^[69]

• Prince Llywelyn ap Gruffudd invades the northern coastal areas that have agreed to English rule (see 1254). Edward (the Lord Edward), who has been given the areas to govern himself by his father, King Henry III, asks him for support but Henry refuses.
• The ancient Irish Kingdom of Breifne splits into East Breifne and West Breifne, after a war between the O'Reillys and the O'Rourkes.

• Venetian–Genoese War: A dispute between Venice and Genoa arises about concerning land in Acre owned by Mar Saba but claimed by both Venice and Genoa – which leads to a Genoese attack of the monastery in the Venetian quarter. The Venetians are supported by Pisa and the Knights Templar, while the Genoese are joined by the Knights Hospitaller.^[70]

• October – The Japanese Kenchō era ends and the Kōgen era begins during the reign of the 13-year-old Emperor Go-Fukakusa.

• June 30 – A large volcanic eruption in Harrat Rahat (near Medina) is associated with an Islamic prophecy.^[71]

• May 4 – Pope Alexander IV issues the papal bull Licet ecclesiae catholicae, constituting the Order of Saint Augustine at Lecceto Monastery.
• August 25 – In Bologna, slavery and serfdom are abolished; this event is recorded in the document called Liber Paradisus (or Heaven Book).

• January 13 – At the first recorded meeting of the college of the seven Electors of the Holy Roman Empire, the 48-year-old Richard of Cornwall (the brother of King Henry III of England) is elected King of the Romans. He is crowned at Aachen, on May 17. His candidacy is opposed by King Alfonso X (the Wise), Pope Alexander IV and King Louis IX (the Saint) favour Alfonso, but both are ultimately convinced by Richard's sister-in-law, Queen Eleanor of Provence, to support Richard.^[72]
• Spring – The Epirote–Nicaean conflict begins between the Despotate of Epirus and the Empire of Nicaea. Despot Michael II Komnenos Doukas revolts and defeats the Nicaean army under George Akropolites. The Epirote and Serbian forces join their attacks against Michael, who sends his forces into Macedonia and marches on to Thessalonica. In response, Michael is attacked – on the west coast of Epirus – by Manfred of Sicily. Manfred first occupies the major Ionian Islands, including Corfu. Then he lands on the Albanian coast and takes Durazzo, Berat, Valona and their environs.^[73]
• The pagan Karelians start a destructive expedition to Sweden in which King Valdemar requests Alexander IV to declare a crusade against them. This leads to the Third Swedish Crusade to Finland (see 1293).

• Battle of Cadfan: An English expeditionary army under Stephen Bauzan is ambushed and defeated by Welsh forces. The English are decimated by devastating guerilla attacks and the Welsh capture the English supply train. Stephen Bauzan is killed along with some 1,000–3,000 of his men. The remaining English flee the battle, Prince Llywelyn ap Gruffudd is said to have been present at the battle, collecting spoils from the fallen English army. According to sources, it is one of the greatest victories of a Welsh army in the field against a much more powerful English force.^[74]
• King Henry III orders the production of a twenty pence, English coin of pure gold. Unfortunately, the bullion value of the coins is about 20% higher than the nominal face value, leading to poor circulation, as coins are melted down by individuals for their gold content.
• Henry III relents to the demands of his son Edward (the Lord Edward) for assistance to fight the Welsh (see 1256). He joins him on a campaign to retake the territories lost to the Welsh forces led by Llywelyn ap Gruffudd.
• Battle of Creadran Cille: Norman invading forces under Maurice FitzGerald are driven out by Gofraid O'Donnell in northern Connacht. Later, FitzGerald is killed in personal combat by O'Donnell, on May 20.^[75]

• Venetian–Genoese War: The Venetian fleet under Admiral Lorenzo Tiepolo breaks through the harbour chain at Acre and destroys several Genoese ships. He also attacks the fortifications but Tiepolo is unable to expel the Genoese garrison (some 800 men strong and armed with 50–60 ballistae), from their quarter of the city throwing up a blockade.^[76]
• April 10 – Izz al-Din Aybak, Mamluk sultan of Egypt, is murdered on orders of his wife, Shajar al-Durr. He is succeeded by his 14-year-old son, Nur al-Din Ali, as ruler of the Mamluk Sultanate (until 1259).

• Spring – Mongol forces under Uriyangkhadai conduct a campaign against local Yi and Lolo tribes in Vietnam. He returns to Gansu and sends messengers to the court of Möngke Khan informing him that Yunnan is firmly under Mongolian control. Möngke Khan honors and rewards Uriyangkhadai for his military achievements.^[77]
• Winter – Mongol forces move down from their base at Hamadan, while Baiju Noyan crosses the Tigris River at Mosul with his army. On the left-wing Kitbuqa enters the plain of Iraq, while Mongol forces under Hulagu Khan advance through Kermanshah.^[78]

• March – The Japanese Kōgen era ends and the Shōka era begins during the reign of the 14-year-old Emperor Go-Fukakusa (until 1259).

• June 5 – The city of Kraków is granted Magdeburg rights by High Duke Bolesław V (the Chaste), having been rebuilt after being nearly destroyed during the Mongol invasion of Poland.

• Louis IX (the Saint) confirms the foundation by his chaplain Robert de Sorbon of the College of Sorbonne in Paris, giving a formal college (and still-common name) to the already existing University of Paris.^[79]

• Matthew Paris, English monk and chronicler, personally interviews Henry III for an entire week while compiling his major work of English history, Chronica Majora.

• Samalas eruption: Mount Samalas volcano erupts on Lombok Island, Indonesia. One of the largest volcanic eruptions in the past 10,000 years, it creates severe climatic changes across the globe, leading to severe famine and death, and to one of the biggest geopolitical changes across the globe over the next few centuries.^[80][81]

• February 10 – Siege of Baghdad: Mongol forces (some 150,000 men), led by Hulagu Khan, besiege and conquer Baghdad after a siege of 13 days. During the first week of February, the eastern walls begin to collapse, and the Mongols swarm into the city, on February 10. Caliph Al-Musta'sim surrenders himself to Hulagu – together with all the Abbasid chief officers and officials. They are ordered to lay down their arms, and are massacred. Hulagu imprisons Al-Musta'sim among his treasures, to starve him to death. Meanwhile, massacres continue throughout the whole city; in 40 days about 80,000 citizens are murdered. The only survivors are the ones who are hiding in cellars which are not discovered, and a number of attractive girls and boys who are kept to be slaves, and the Christian community, who take refuge in the churches which are left undisturbed, by the special orders of Hulagu's wife, Doquz Khatun.^[82]
• February 15 – Hulagu Khan enters Baghdad, where many quarters of the city are ruined by fire. The Great Library (or House of Wisdom) is destroyed, numerous precious book collections are thrown into the Tigris River. Before the siege, about 400,000 manuscripts are rescued by Nasir al-Din al-Tusi, Persian polymath and theologian, who takes them to Maragheh (located in East Azerbaijan Province). The sack of Baghdad brings an end to the Abbasid Caliphate (750-1258) and the Islamic Golden Age. Many professors, physicians, scientists, clerics, artists and lecturers are also massacred.

• May 11 – Treaty of Corbeil: King Louis IX (the Saint) signs a peace treaty with King James I (the Conqueror). Louis, heir of Charlemagne, formally renounces his feudal overlordship over Catalonia (independent de facto since 988), while James renounces his claims over Occitania.
• June – War of the Euboeote Succession: Achaean forces under William II Villehardouin defeat a coalition of Greek princes led by Guy I de la Roche (Great Lord), duke of Athens, which ends the conflict, on August 6.
• August 10 – Manfred, son of the late Emperor Frederick II, is crowned king of Sicily at Palermo. Pope Alexander IV, who has an alliance with the Saracens, declares the coronation void and excommunicates Manfred.
• August 16 – Theodore II (Laskaris) dies after a 4-year reign at Magnesia. He is succeeded by his 7-year-old son, John IV, as ruler of the Empire of Nicaea. His regent becomes the bureaucrat George Mouzalon.^[83]
• August 25 – George Mouzalon is assassinated in Magnesia ad Sipylum, as part of a conspiracy led by Byzantine nobles, under future Emperor Michael VIII (Palaiologos).
• Gissur Þorvaldsson, Icelandic chieftain (or goði), is made Earl of Iceland for his loyal service to King Haakon IV (the Old).

• May 2 – King Henry III accepts the demand of Simon de Montfort and his baronial supporters that the government is reformed with a committee of 22 barons, including the king. As an act of faith, Simon de Montfort hands over his estates at Odiham and Kenilworth as part of the proposals. The Provisions of Oxford establish baronial control of the government, also known as the Oxford Parliament, on June 11.^[84][85]

• Llywelyn ap Gruffudd proclaims himself Prince of Wales, first used in an agreement between Llywelyn and his supporters and the Scottish nobility. He becomes the final ruler of an independent Wales before its conquest by King Edward I of England (Edward Longshanks).

• June 25 – Battle of Acre: The Genoese send an armada (some 50 galleys) to relieve the blockade at Acre and ask for the assistance of Philip of Montfort, lord of Tyre, and the Knights Hospitaller for a combined attack from the land side. The Genoese fleet's arrival takes the Venetians by surprise but the superior experience and seamanship result in a crushing Venetian victory, with half the Genoese ships lost. Later, the Genoese garrison is forced to abandon Acre.^[86][87]

• Mongol invasions of Vietnam: Mongol forces (some 30,000 men) under Uriyangkhadai, son of Subutai, invade Vietnam. After many battles, the Vietnam army is routed and defeated. The senior leaders are able to escape on pre-prepared boats, while the remnants are destroyed on the banks of the Red River. The Mongols occupy the capital city, Thăng Long (modern-day Hanoi), and massacres the city's inhabitants, by the end of January.^[88]

• The consequences of the volcanic Samalas eruption (see 1257) in Indonesia include the following anecdotal accounts: very dry fog in France; lunar eclipses in England; severe winter in Europe; a harsh spring in Iceland; famine in England, Germany, France and Italy; and pestilence in London, parts of France, Austria, Iraq, Syria, and southeast Turkey.^[89]

• In Genoa, the Republic starts imposing forced loans, known as luoghi, to its taxpayers; they are a common resource of medieval public finance.^[90]

• Civil unrest in northern Italy spawns the medieval musical form of Geisslerlieder, penitential songs sung by wandering bands of Flagellants.
• Kudahuvadhoo is converted to Islam

• September – Battle of Pelagonia: The Empire of Nicaea defeats the Principality of Achaea, ensuring the eventual reconquest of Constantinople in 1261.^[91][92]
• December 4 – Kings Louis IX of France and Henry III of England agree to the Treaty of Paris, in which Henry renounces his claims to French-controlled territory on continental Europe (including Normandy), in exchange for Louis withdrawing his support for English rebels.^[93]
• The famous frescoes of the Boyana Church in Bulgaria are completed (the church and its murals are now a UNESCO World Heritage Site).^[94]
• The German cities of Lübeck, Wismar, and Rostock enter into a pact to defend against pirates of the Baltic Sea, laying the groundwork for the Hanseatic League.^[95]
• Nogai Khan leads the second Mongol Golden Horde attack against Lithuania, and Poland.^[96]
• Epirote–Nicaean conflict.^[97]

• August 11 – While conducting a siege against the Song dynasty city known as Fishing Town in the province of Chongqing, China, the Mongol Great Khan, Möngke Khan, dies in the nearby hills. Persian, Chinese, and Mongol records have different accounts of how he died, including succumbing to an arrow wound received by a Chinese archer in the siege, dysentery, and even a cholera epidemic. His death sparks a succession crisis in the Mongol Empire, while his brothers Ariq Böke and Kublai soon convene their own kurultai to elect themselves as the next Khan of Khans, opening the path to a four–year-long Toluid Civil War from 1260 to 1264. In the end, Ariq Böke surrenders to Kublai.^[98][99]
• While engaged in a war with the Mongols, the Song Chinese official Li Zengbo writes in his Kozhai Zagao, Xugaohou that the city of Qingzhou is manufacturing one to two thousand strong iron-cased gunpowder bomb shells a month, dispatching to Xiangyang and Yingzhou about ten to twenty thousand such bombs at a time.^[100]
• Lannathai, a kingdom in the north of Thailand, is founded by King Mangrai.^[101][102]
• The Goryeo Kingdom in Korea surrenders to invading Mongol forces.^[103]
• The Chinese era Kaiqing begins and ends, in the Northern Song dynasty of China.^[104]
• The Japanese Shōka era ends, and the Shōgen era begins.^[105][106]