1252

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 (Neumark).
• The Lithuanian city of Klaipėda (Memel) 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.
• The Mongols take the westernmost province of the Song dynasty empire.

• March 25 – Conradin, Duke of Swabia (d. 1268)
• Safi-ad-din Ardabili, Persian Sufi leader
• Eleanor de Montfort, Princess of Wales, English-born consort (d. 1282)

• 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 (b. 1196)
• 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 (b. 1218)
• 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 (b. 1188)
• 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^{[citation needed]}
  • Yesü Möngke, Khan of the Chagatai Khanate