📅 Today in HistoryFebruary 13

Emperor Otto I and Pope John XII co-sign the Diploma Ottonianum, recognizing John as ruler of Rome.

Siege of Baghdad: Hulegu Khan, a prince of the Mongol Empire, orders his army to sack and plunder the city of Baghdad, which they had just captured.

The central tower of Ely Cathedral falls on the night of 12th-13th.

War of the Straits: The Battle of the Bosporus is fought in a stormy sea into the night between the Genoese, Venetian, Aragonese, and Byzantine fleets.

The Treaty of Westminster is finalised between Edward IV of England and the Scottish Lord of the Isles.

Challenge of Barletta: Tournament between 13 Italian and 13 French knights near Barletta.

Catherine Howard, the fifth wife of Henry VIII of England, is executed for adultery.

Galileo Galilei arrives in Rome for his trial before the Inquisition.

The Clergy Act becomes law, excluding bishops of the Church of England from serving in the House of Lords.

With the accession of young Charles XI of Sweden, his regents begin negotiations to end the Second Northern War.