📅 Today in HistorySeptember 23

Drusilla, Caligula's sister who died in June, with whom the emperor is said to have an incestuous relationship, is deified.

Pope Callixtus II and Holy Roman Emperor Henry V agree to the Concordat of Worms to put an end to the Investiture Controversy.

The Battle of Arnemuiden, in which a French force defeats the English, is the first naval battle of the Hundred Years' War and the first naval battle in which gunpowder artillery is used.

The Battle of Kherlen is the second significant victory over Ming dynasty China by the Mongols since 1368.

The Battle of Blore Heath, the first major battle of the English Wars of the Roses, is won by the Yorkists.

King Philip II of Spain issues cedula, ordering a halt to colonizing efforts in Florida.

First English Civil War: The Battle of Powick Bridge, the first engagement between the primary field armies of the Royalists and the Parliamentarians, ends in a Royalist victory.

American Revolutionary War: John Paul Jones, naval commander of the United States, on board the USS Bonhomme Richard, wins the Battle of Flamborough Head.

Second Anglo-Maratha War: The Battle of Assaye is fought between the British East India Company and the Maratha Empire in India.

Tripolitsa, Greece, is captured by Greek rebels during the Greek War of Independence.