| 23 May 1125 | Germany, Holy Roman Empire [births and deaths] | Henry V, German king 1099–1125 and Holy Roman Emperor 1111–25, the last emperor of the Salian dynasty, dies in Utrecht, in the modern Netherlands (38). |
| 23 May 1192 | England, Palestine, Ayyubid Sultanate [Crusades (1095–1272)] | King Richard I the Lionheart of England takes Daron, thus completing the recovery of the Palestinian coast from Saladin, Sultan of Egypt and Syria. |
| 23 May 1430 | France, England [Hundred Years War (1337–1453)] | Burgundian troops capture the French military leader Joan of Arc as she attempts to prevent the fall of the town of Compiègne, France. She is sold to the English for 10,000 livres tournois. |
| 23 May 1493 | France, Holy Roman Empire [treaties] | King Charles VIII of France restores Artois and Franche-Comté (the county of Burgundy) to the Holy Roman Empire under the Treaty of Senlis. He received it as the dowry of Margaret of Austria, whom he has now forsaken for Anne of Brittany. |
| 23 May 1498 | Florence [political events] | Girolamo Savonarola, Italian religious leader and messianic Preacher, effective ruler of Florence, Italy, (1494–98), who was excommunicated in June 1497 for disobeying a ban on his preaching and for his criticism of the pope, is strangled and burnt in Florence, Italy, for seeking the deposition of Pope Alexander VI (45). Savonarola was responsible for making Florence a democratic republic. |
| 23 May 1526 | Papal States, Venice, Florence, France, Milan, England, Italy, Holy Roman Empire [political events] | Pope Clement VII forms the Holy League of Cognac against the Holy Roman Emperor Charles V with Venice, Florence, and France; Duke Francesco Sforza II of Milan joins later, while King Henry VIII of England allows himself to be named ‘Protector’. The League aims to restore the autonomy of the Italian states and to reverse the Treaty of Madrid of 14 January. |
| 23 May 1555 | Rome [Catholicism] | The Italian churchman Gian Pietro Carafa is elected Pope Paul IV following the death of Pope Marcellus II. He is pope until 1559. |
| 23 May 1618 | Bohemia, Habsburg Monarchy, Holy Roman Empire [Thirty Years War (1618–48)] | Protestant rebels led by Count Heinrich von Thurn assault King Ferdinand II of Bohemia's councillors Jaroslav Martinic and Vilém Slawata. The councillors flee after being thrown out of a window in Hradcany Castle in Prague. The incident, known as the Defenestration of Prague, marks the beginning of the Thirty Years' War. |
| 23 May 1798 | Ireland, UK [revolution] | A rebellion of United Irishmen and Catholic Irish nationalists against British rule breaks out in Ireland. |
| 23 May 1906 | [births and deaths] | Henrik Ibsen, Norwegian poet and playwright whose works include Peer Gynt (1867) and A Doll's House (1879), dies in Christiania (now Oslo), Norway (78). |
| 23 May 1926 | Lebanon, France [political events] | France proclaims the Lebanon (part of the territory mandated to it by the League of Nations) a republic. |
| 23 May 1937 | USA [births and deaths] | John D Rockefeller, US industrialist who founded Standard Oil, and philanthropist who founded the Rockefeller Foundation, dies in Ormond Beach, Florida (97). |
| 23 May 1945 | Germany [births and deaths] | Heinrich Himmler, German Nazi leader, head of the SS, and organizer of the Nazi death camps, commits suicide after being captured in Lüneberg, Germany (44). |
| 23 May 1949 | West Germany [political events] | The Federal Republic of Germany (West Germany) comes into being, with Bonn as its capital. West Berlin is excluded from the new state but associated with it. |
| 23 May 1972 | Rhodesia, UK [political events] | Britain abandons its Rhodesian settlement proposals when the Pearce Commission reports that black opinion is unfavourable. |
| 23 May 1997 | Belarus, Russia [treaties] | A Union Charter linking Belarus and Russia and aiming at eventual unification of the two countries is signed by presidents Alexander Lukashenko and Boris Yeltsin. |
