1251

• April – The first Shepherds' Crusade, a domestic French uprising in response to events in Egypt during the Seventh Crusade, occurs.{{Cite book|url=https://books.google.com/books?id=u5DdBwAAQBAJ&q=1251+Shepherds%27+Crusade&pg=PA218|title=The Crusades to the Holy Land: The Essential Reference Guide: The Essential Reference Guide|last=Dickson|first=Gary|publisher=ABC-CLIO|year=2015|isbn=9781610697804|editor-last=Murray|editor-first=Alan V.|location=Santa Barbara, CA, Denver, CO and Oxford|pages=217–218|language=en}}{{Cite book|url=https://books.google.com/books?id=HG_IBgAAQBAJ&q=1251+Shepherds%27+Crusade&pg=PA27|title=Holy War, Martyrdom, and Terror: Christianity, Violence, and the West|last=Buc|first=Philippe|publisher=University of Pennsylvania Press|year=2015|isbn=9780812290974|location=Philadelphia, PA|pages=172|language=en}}
• May – English governor Simon de Montfort suppresses a revolt in Gascony.{{cite book|last=Williams|first=Hywel|title=Cassell's Chronology of World History|url=https://archive.org/details/cassellschronolo0000will/page/141|url-access=registration|location=London|publisher=Weidenfeld & Nicolson|year=2005|isbn=0-304-35730-8|pages=[https://archive.org/details/cassellschronolo0000will/page/141 141–144]}}
• December 26 – King Alexander III of Scotland marries Margaret, daughter of King Henry III of England, precipitating a power struggle between the two monarchs.{{Cite book|url=https://books.google.com/books?id=OIK2WHQkdCgC&q=1251+Alexander+III+Scotland+Margaret&pg=PA142|title=Henry III of England and the Staufen Empire, 1216-1272|last=Weiler|first=Björn K. U.|publisher=Boydell & Brewer|year=2006|isbn=9780861932801|location=Woodbridge, UK and Rochester, NY|pages=142|language=en}}{{Cite book|url=https://books.google.com/books?id=6KJVAAAAcAAJ&q=1251+Alexander+III+Scotland+Margaret&pg=PA16|title=A Genealogical History of the English Sovereigns, from William I. to George III. inclusive, accompanied with A brief Statement of the principal Events in each Reign; Biographical notices of all the noble families connected with the royal houses; and illustrated by genealogical tables|last=Toplis|first=William|publisher=Thomas Underwood|year=1814|location=London|pages=16|language=en}}
• 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.{{Cite book|url=https://books.google.com/books?id=o44cBQAAQBAJ&q=1251+Andrew+of+Longjumeau&pg=PA47|title=The Mongol Empire between Myth and Reality: Studies in Anthropological History|last=Aigle|first=Denise|publisher=BRILL|year=2014|isbn=9789004280649|location=Leiden, Boston|pages=47|language=en}}{{Cite book|url=https://books.google.com/books?id=YQleM5Yc0VAC&q=1251+Andrew+of+Longjumeau&pg=PA161|title=Storm from the East: From Genghis Khan to Khubilai Khan|last=Marshall|first=Robert|publisher=University of California Press|year=1993|isbn=9780520083004|location=Berkeley, CA and Los Angeles, CA|pages=161–162|language=en}}
• Mindaugas of Lithuania is baptized, in prelude to his crowning as King of Lithuania in 1253.{{Cite book|url=https://books.google.com/books?id=L9X3CwAAQBAJ&q=1251+Mindaugas&pg=PA48|title=The Lithuanian Millennium: History, Art and Culture|last1=Janonienė|first1=Rūta|last2=Račiūnaitė|first2=Tojana|last3=Iršėnas|first3=Marius|last4=Butrimas|first4=Adomas|publisher=Vilnius Academy of Arts Press|year=2015|isbn=9786094470974|location=Vilnius, Lithuania|pages=48|language=en}}
• Alexander Nevsky signs the first peace treaty between Kievan Rus' and Norway.{{Cite book|url=https://books.google.com/books?id=wb1kAwAAQBAJ&q=1251+Alexander+Nevsky+norway&pg=PA141|title=In Northern Mists: Arctic Exploration in Early Times|last=Nansen|first=Fridtjof|publisher=Cambridge University Press|year=2014|isbn=9781108071697|volume=2|location=Cambridge and New York|pages=141|language=en|translator-last=Arthur G. Chater|orig-date=1911}}{{Cite book|url=https://books.google.com/books?id=cYU0DwAAQBAJ&q=1251+Alexander+Nevsky+norway&pg=PT20|title=Architectural Conservation and Restoration in Norway and Russia|last1=Khodakovsky|first1=Evgeny|last2=Lexau|first2=Siri Skjold|publisher=Routledge|year=2017|isbn=9781351995658|location=New York and London|language=en}}{{Cite book|url=https://books.google.com/books?id=UTCJAAAAQBAJ&q=1251+Alexander+Nevsky+norway&pg=PA86|title=CultureShock! Russia: A Survival Guide to Customs and Etiquette|last=Pavloskaya|first=Anna|publisher=Marshall Cavendish International Asia|year=2011|isbn=9789814435574|location=Tarrytown, NY|pages=86|language=en}}
• King Conrad IV of Germany invades Italy, but fails to subdue the supporters of Pope Innocent IV.{{Cite book|url=https://books.google.com/books?id=E2CTAgAAQBAJ&q=1251+Conrad+IV+of+Germany+italy&pg=PT277|title=Medieval Italy: An Encyclopedia|last=Sodders|first=Daniel R.|publisher=Routledge|year=2004|isbn=9781135948801|editor-last=Kleinhenz|editor-first=Christopher|location=New York and London|pages=247|language=en}}{{Cite book|url=https://books.google.com/books?id=R63ACQAAQBAJ&q=1251+Conrad+IV+of+Germany+italy&pg=PA403|title=World Monarchies and Dynasties|last=Middleton|first=John|publisher=Routledge|year=2015|isbn=9781317451587|location=New York and London|pages=403|language=en}}
• Ottokar II of Bohemia, later to become King of Bohemia, is elected Duke of Austria.{{Cite book|url=https://books.google.com/books?id=zfxITVc66KMC&q=1251+Ottokar+Bohemia&pg=PA51|title=Bohemia in History|last=Teich|first=Mikulas|publisher=Cambridge University Press|year=1998|isbn=9780521431552|location=Cambridge, New York and Melbourne|pages=51|language=en}}{{Cite book|url=https://books.google.com/books?id=5qgHE29pikMC&q=1251+Ottokar+Bohemia&pg=PA46|title=The History of the Czech Republic and Slovakia|last=Mahoney|first=William|publisher=ABC-CLIO|year=2011|isbn=9780313363061|location=Santa Barbara, CA, Denver, CO and Oxford|pages=46|language=en}}
• The earliest known manuscript of The Proverbs of Alfred, a collection of sayings of England's Alfred the Great, is written.{{Cite book|url=https://books.google.com/books?id=LXyyYs2cRDcC&q=1251+The+Proverbs+of+Alfred&pg=PT20|title=Encyclopedia of the Literature of Empire|last=Snodgrass|first=Mary Ellen|publisher=Infobase Publishing|year=2010|isbn=9781438119069|series=Facts on File Library of World Literature|location=New York|pages=9–10|language=en}}

• April 21 – City of Launggyet in Arakan (modern-day Burma) is founded according to some sources.Rakhine Razawin Thit.
• July 1 – Möngke Khan is elected as the fourth great Khan of the Mongol Empire.{{Cite book|chapter-url=https://books.google.com/books?id=RgpRDAAAQBAJ&q=1251+M%C3%B6ngke+Khan&pg=PA90|title=The Mongols' Middle East: Continuity and Transformation in Ilkhanid Iran|last=De Nicola|first=Bruno|publisher=BRILL|year=2016|isbn=9789004314726|editor-last=De Nicola|editor-first=Bruno|location=Leiden, Boston|pages=89|language=en|chapter=The Economic Role of Mongol Women: Continuity and Transformation from Mongolia to Iran|editor-last2=Melville|editor-first2=Charles}}{{Cite book|url=https://books.google.com/books?id=4jjvBQAAQBAJ&q=1251+M%C3%B6ngke+Khan&pg=PA144|title=A History of War in 100 Battles|last=Overy|first=R. J.|publisher=Oxford University Press|year=2014|isbn=9780199390717|location=Oxford and New York|pages=144|language=en}}
• The carving of the Tripitaka Koreana, a collection of Buddhist scriptures recorded on some 81,000 wooden blocks, is completed.{{Cite book|url=https://books.google.com/books?id=iB8R0oEH3kEC&q=1251+Tripitaka+Koreana&pg=PA139|title=The Land of Scholars: Two Thousand Years of Korean Confucianism|last1=Kang|first1=Chae-ŏn|last2=Kang|first2=Jae-eun|publisher=Homa & Sekey Books|year=2006|isbn=9781931907378|location=Paramus, NJ|pages=139|language=en}}{{Cite book|chapter-url=https://books.google.com/books?id=N3z1OjL4KY0C&q=1251+Tripitaka+Koreana&pg=PA157|title=Korea and Globalization: Politics, Economics and Culture|last=Jong-myung|first=Kim|publisher=Routledge|year=2013|isbn=9781136859786|editor-last=Lewis|editor-first=James B.|location=New York and London|pages=157|language=en|chapter=The Tripitạka Koreana: Its Computerization and Significance for the Cultural Sciences in a Modern Globalized World|editor-last2=Sesay|editor-first2=Amadu}}

• June 5 – Hōjō Tokimune, 8th regent of the Kamakura shogunate (d. 1284){{Cite book|url=https://books.google.com/books?id=RHXG0JV9zEkC&q=1251+Hojo+Tokimune&pg=PA129|title=Japan at War: An Encyclopedia|last=Perez|first=Louis G.|publisher=ABC-CLIO|year=2013|isbn=9781598847413|location=Santa Barbara, CA, Denver, CO and Oxford|pages=129|language=en}}{{Cite book|url=https://books.google.com/books?id=YUViYC0jyBQC&q=1251+Hojo+Tokimune&pg=PR11|title=Zen Sanctuary of Purple Robes: Japan's Tokeiji Convent Since 1285|last1=Morrell|first1=Sachiko Kaneko|last2=Morrell|first2=Robert E.|publisher=State University of New York Press|year=2012|isbn=9780791481448 |page=xi|language=en}}
• September 2 – Francis of Fabriano, Italian writer (d. 1322){{Cite book|url=https://books.google.com/books?id=hZQ0DgAAQBAJ&q=1251+Francis+of+Fabriano&pg=PT55|title=Champions of the Rosary: The History and Heroes of a Spiritual Weapon|last=Calloway|first=Donald H.|publisher=Marian Press|year=2016|isbn=9781596143937|location=Stockbridge, MA|language=en}}
• Adelaide, Countess of Auxerre, French countess (d. 1290){{cite book|first=Alice|last=Saunier-Seïté|title=Les Courtenay: Destin d'une illustre famille bourguignonne|publisher=éditions France-Empire|year=1998|isbn=2-7048-0845-7}}

• January – Bohemund V of Antioch{{Cite book|chapter-url=https://books.google.com/books?id=TKaPrQPFIAMC&q=1251+Bohemond+V&pg=PA404|title=A History of the Crusades: The Impact of the Crusades on Europe|last=Porteous|first=John|publisher=University of Wisconsin Press|year=1989|isbn=9780299107444|editor-last=Setton|editor-first=Kenneth Meyer|volume=VI: The Impact of the Crusades on Europe|location=Madison, WI|pages=404|language=en|chapter=Crusader Coinage with Greek and Latin Inscriptions|editor-last2=Hazard|editor-first2=Harry W.|editor-last3=Zacour|editor-first3=Norman P.}}{{Cite book|url=https://books.google.com/books?id=PEsM1ibpcJQC&q=1251+Bohemond+V&pg=PA19|title=Kings, Rulers, and Statesmen|last1=Wise|first1=Leonard F.|last2=Hansen|first2=Mark Hillary|last3=Egan|first3=E. W.|publisher=Sterling Publishing Company, Inc.|year=2005|isbn=9781402725920|location=New York|pages=19|language=en|orig-date=1967}}
• February 9 – Matthias II, Duke of Lorraine{{Cite book|url=https://books.google.com/books?id=486s3eMkLfgC&q=1251+Matthias+II+Lorraine&pg=PA762|title=Biographical Index of the Middle Ages|last=Wispelwey|first=Berend|publisher=Walter de Gruyter|year=2008|isbn=9783110914160|location=Munich, Germany|pages=762|language=en}}
• March 6 – Rose of Viterbo, Italian saint (b. 1235){{Cite book|chapter-url=https://books.google.com/books?id=QkTDDScAgiEC&q=1251+Rose+of+Viterbo&pg=PA46|title=Franciscans and Preaching: Every Miracle from the Beginning of the World Came about Through Words|last=Pryds|first=Darleen|publisher=BRILL|year=2012|isbn=9789004231290|editor-last=Johnson|editor-first=Timothy|location=Leiden, Boston|pages=45–46|language=en|chapter=Franciscan Lay Women and the Charism to Preach}}{{Cite book|url=https://books.google.com/books?id=XlvZ_ja-FN4C&q=1251+Rose+of+Viterbo&pg=PA376|title=Sainthood in the Later Middle Ages|last=Vauchez|first=Andri|publisher=Cambridge University Press|year=2005|isbn=9780521619813|location=Cambridge and New York|pages=376|language=en|orig-date=1988}}
• March 31 – William of Modena, Bishop of Modena{{Cite book|url=https://books.google.com/books?id=GREWu1KjJJAC&q=1251+William+of+Modena&pg=PA91|title=The Chronicle of Prussia by Nicolaus von Jeroschin: A History of the Teutonic Knights in Prussia, 1190–1331|last=Fischer|first=Dr Mary|publisher=Ashgate Publishing, Ltd.|year=2013|isbn=9781409481942|series=Crusade Texts in Translation|volume=20|location=Surrey, UK and Burlington, VT|pages=91|language=en}}{{Cite book|chapter-url=https://books.google.com/books?id=xkEHDAAAQBAJ&q=1251+William+of+Modena&pg=PA7|title=Crusading and Chronicle Writing on the Medieval Baltic Frontier: A Companion to the Chronicle of Henry of Livonia|last=Brundage|first=James A.|publisher=Routledge|year=2016|isbn=9781317156796|editor-last=Tamm|editor-first=Marek|location=New York and London|pages=7|language=en|chapter=Introduction: Henry of Livonia, The Writer and his Chronicle|editor-last2=Kaljundi|editor-first2=Linda|editor-last3=Jensen|editor-first3=Carsten Selch}}
• June 6 – William III of Dampierre, Count of Flanders{{Cite book|chapter-url=https://books.google.com/books?id=Z__RJAZPhHsC&q=1251+William+of+Dampierre&pg=PA85|title=Queens, Regents and Potentates|last=Nicholas|first=Karen|publisher=Boydell & Brewer|year=1993|isbn=9780851156491|editor-last=Vann|editor-first=Theresa M.|location=Cambridge and Dallas, TX|pages=85|language=en|chapter=Women as Rulers: countesses Jeanne and Marguerite of Flanders}}{{Cite book|url=https://books.google.com/books?id=WhmtAgAAQBAJ&q=1251+William+of+Dampierre&pg=PA157|title=Medieval Flanders|last=Nicholas|first=David M.|publisher=Routledge|year=2014|isbn=9781317901556|location=Nee York and London|pages=157|language=en}}
• date unknown
• Winter 1251–52 – Eljigidei, Mongol commander of Persia, killed{{Cite book|url=https://books.google.com/books?id=CCXRCwAAQBAJ&q=1251+Eljigidei&pg=PA183|title=Byzantium and the Turks in the Thirteenth Century|last=Korobeinikov|first=Dimitri|publisher=Oxford University Press|year=2014|isbn=9780191017940|location=Oxford and New York|pages=183|language=en}}{{Cite book|url=https://books.google.com/books?id=LhiWDwAAQBAJ&q=1251+Eljigidei&pg=PA205|title=The History of Central Asia: The Age of Islam and the Mongols|last=Baumer|first=Christoph|publisher=Bloomsbury Publishing|year=2016|isbn=9781838609405|location=London and New York|pages=205|language=en}}
• Isobel of Huntingdon, Scots noblewoman (b. 1199){{Cite book|url=https://books.google.com/books?id=l0-JEaL-4uIC&q=1251+Isobel+of+Huntingdon&pg=PA186|title=Family of Hay|last=Colcock|first=Charles Jones|publisher=Pelican Publishing|year=1959|isbn=9781455604050|location=Gretna, LA|pages=186|language=en}}
• Oghul Qaimish, 3rd regent of the Mongol Empire, following her husband's death{{Cite book|url=https://books.google.com/books?id=4gB9DQAAQBAJ&q=1251+Oghul+Qaimish&pg=PA169|title=The Mongol Empire: A Historical Encyclopedia|last=Hamil|first=Donna|publisher=ABC-CLIO|year=2016|isbn=9781610693400|editor-last=May|editor-first=Timothy|volume=I|location=Santa Barbara, CA, Denver, CO and Oxford|pages=169–170|language=en}}{{Cite book|url=https://books.google.com/books?id=zi1WDwAAQBAJ&q=1251+Oghul+Qaimish&pg=PA76|title=Women in Mongol Iran: The Khatuns, 1206-1335|last=Nicola|first=Bruno De|publisher=Edinburgh University Press|year=2017|isbn=9781474415484|location=Edinburgh and Stockport|pages=76|language=en}}

{{Reflist}}

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