May 23 in Military History

Joan of Arc was captured by Burgundian forces after a failed sortie from the besieged town of Compiegne. Her trial and execution by the English the following year transformed her into a French national symbol whose influence on French military identity continued through the twentieth century.

Archbishop Cranmer declared Henry VIII's marriage to Catherine of Aragon null and void, a decision that led to England's break with Rome and had profound military consequences as England became a Protestant power.

Admiral Yi Sun-sin of the Joseon Korean navy defeated a Japanese squadron at Okpo on the first combat deployment of his reformed fleet. The engagement began the seven-year naval campaign in which Yi's improved ships and tactics became among the most admired in the history of naval warfare.

Bohemian Protestant nobles threw two imperial Catholic regents and a secretary from the windows of Prague Castle, beginning the revolt that triggered the Thirty Years War. The conflict that followed killed roughly eight million people and reshaped European state-building and military organization.

The Duke of Marlborough's Allied forces decisively defeated the French at Ramillies in the Spanish Netherlands, one of the most decisive battles of the War of the Spanish Succession.

Grant launched major assaults against the Confederate fortress at Vicksburg, Mississippi, which were repulsed with heavy casualties, leading him to settle in for a prolonged siege.

The Kingdom of Italy formally declared war on Austria-Hungary, entering the First World War on the side of the Entente after signing the secret Treaty of London a month earlier. The Italian front ran for 650 kilometers along the Alpine and Isonzo frontiers and produced some of the most costly terrain combat of the war.

The submarine USS Squalus sank during a test dive off the New Hampshire coast when a valve failed, trapping 59 crew members. A dramatic rescue operation saved 33 men in one of the first successful uses of the McCann Rescue Chamber.

Reichsführer-SS Heinrich Himmler bit down on a cyanide capsule during a medical examination after being captured by British forces near Bremervörde.

Egyptian President Gamal Abdel Nasser announced the closure of the Strait of Tiran to Israeli-flagged vessels and to ships carrying strategic cargo to the Israeli port of Eilat. The move converted the UNEF withdrawal crisis into a direct casus belli under Israeli policy and made the Six-Day War nearly inevitable.

NATO and Russia formally established the NATO-Russia Council at a summit in Rome, creating a new framework for consultation and cooperation on security issues in the post-9/11 era.