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.
• 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 masters 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.