1252
Year 1252 was a leap year starting on Monday of the Julian calendar.
Events
By place
Europe
- April 6 - Saint Peter of Verona is assassinated by Carino of Balsamo.
- 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.
- June 1 - Alfonso X is proclaimed king of Castile and León.
- July - The settlement of Stockholm in Sweden is founded, by Birger Jarl.
- December 25 - Christopher I of Denmark is crowned King of Denmark, in the Lund Cathedral.
- The Polish land of Lebus is incorporated into the German state of Brandenburg, marking the start of Brandenburg's expansion into previously Polish areas.
- The Lithuanian city of Klaipėda is founded by the Teutonic Knights.
- The town and monastery of Orval Abbey in Belgium burn to the ground; rebuilding takes 100 years.
- Thomas Aquinas travels to the University of Paris, to begin his studies there for a master's degree.
- In astronomy, work begins on the recording of the Alfonsine tables.
Asia
- The classic Japanese text Jikkunsho is completed.
- The Chinese era Chunyou ends.
- Mongol conquest of the Song dynasty: the Mongols take the westernmost province of the Song dynasty empire.
Births
- March 25 - Conradin, Duke of Swabia
- Safi-ad-din Ardabili, Persian Sufi leader
- Eleanor de Montfort, Princess of Wales, English-born consort
Deaths
- January 1 - Saint Zdislava Berka, Bohemian lay Dominican benefactress
- January 23 - Isabella, Queen of Armenia
- January - Bohemond V, [Prince of Antioch]
- February 3 - Sviatoslav III of Vladimir, Prince of Novgorod
- April 1 - Kujō Michiie, Japanese regent
- April 6 - Saint Peter of Verona
- May 3 or May 4 - Günther von Wüllersleben, Grand Master of the Teutonic Knights
- May 30 - King Ferdinand III of Castile and Leon
- June 6 - Robert Passelewe, Bishop of Chichester
- June 9 - Otto I, Duke of Brunswick-Lüneburg
- June 29 - Abel, King of Denmark
- August 1 - Giovanni da Pian del Carpine, Italian chronicler of the Mongol Empire
- November 27 - Blanche of Castile, queen of Louis VIII of France and regent of France date unknown
- *John of Basingstoke, English scholar and ecclesiastic
- *Henry I, Count of Anhalt
- *Sorghaghtani Beki, Mongolian empress and regent
- *Catherine Sunesdotter, Swedish queen consort
- *Yesü Möngke, Khan of the Chagatai Khanate