| 21 July 905 | Italy, Provence [wars] | Berengar of Friuli, the deposed king of Italy, captures the emperor, Louis III, at Verona, blinds him, and expels him from Italy back to his kingdom of Provence. |
| 21 July 971 | Byzantine Empire, Kiev [Byzantine reconquests (963–1025)] | The Byzantine emperor John Tzimisces again defeats Prince Svjatoslav I of Kiev and compels him to evacuate the Balkans and the Crimea. |
| 21 July 1242 | England, France, Toulouse [wars] | King Henry III of England retreats to Saintes after he is defeated by King Louis IX of France at Taillebourg, France. Louis suppresses the revolt of Raymond VII, Count of Toulouse, and the Lusignans. |
| 21 July 1403 | England [political events] | King Henry IV of England defeats and kills Henry ‘Hotspur’, son of the Earl of Northumberland, at Shrewsbury, England, so ending his revolt and preventing him from joining forces with the Welsh rebels. |
| 21 July 1425 | Byzantine Empire [administration] | The Byzantine emperor Manuel II, who has ruled only Constantinople (modern Istanbul, Turkey) while his brothers have ruled other remaining fragments of the empire in Greece, dies. He is succeeded by his eldest son, John VIII. |
| 21 July 1667 | United Netherlands, France, West Indies, UK [treaties] | The Peace of Breda ends the second Anglo-Dutch war. England makes a treaty with France to cede Acadia in North America and recover Antigua, Montserrat, and St Kitts in the West Indies. A second treaty between England and the United Netherlands allows the Dutch to retain Surinam in the West Indies and England the Dutch colonies of New Netherland, Cape Coast Castle, and Fort James. |
| 21 July 1718 | Habsburg Monarchy, Ottoman Empire [Habsburg–Ottoman Wars (1525–1718)] | The Peace of Passarowitz ends the war between the Habsburg Monarchy and the Ottoman Empire. By its terms, signed through British and Dutch mediation (the eastern trade of both states had been disrupted by the war), Austria completes its occupation of Hungary, and gains Belgrade and a strip of Serbia and Bosnia, the Banat of Temesvár (now part of Hungary), and Little Wallachia; Venice, in alliance with Austria since 1716, retains Corfu and its conquests in Albania and Dalmatia; the Ottoman Empire keeps the Morea (the Peloponnese) and the island of Aegina, in Greece. The parties agree to adhere to this agreement for at least 25 years. |
| 21 July 1774 | Ottoman Empire, Russia [treaties] | Under the Treaty of Kuchuk-Kainardzhi, the Ottoman Empire cedes the Black Sea coast from the River Bug to the River Dnieper to Russia, and also the Crimean ports of Yenikale and Kertch. Moldavia and Wallachia are returned to the Ottoman Empire, and the Khanate of the Crimea is recognized as independent. |
| 21 July 1798 | France, Egypt-Ottoman [French Revolutionary Wars (1792–1801)] | Napoleon Bonaparte's French army in Egypt, having occupied Alexandria, defeats Mameluke forces at the Battle of the Pyramids. French domination of Egypt is established. |
| 21 July 1861 | USA [American Civil War (1861–65)] | The Confederates gain an indecisive victory over the Union army in the Battle of Bull Run in Virginia, the first major military engagement of the American Civil War. |
| 21 July 1899 | USA [births and deaths] | Ernest Hemingway, US novelist who writes A Farewell to Arms (1929) and For Whom the Bell Tolls (1941), born in Oak Park, Illinois (–1961). |
| 21 July 1921 | Spain, Morocco [wars] | Spanish troops under General Fernandez Silvestre waging a campaign against the Riffians in Morocco are defeated by troops led by Abd al-Karim; 12,000 are killed. |
| 21 July 1959 | USA [fiction] | A US federal district court in New York City lifts the ban that the Postmaster General had placed on Lady Chatterley's Lover by English author D H Lawrence, ruling that the novel, which was privately published in Florence in 1928, is not obscene. A complete edition is published. |
| 21 July 2004 | UK [physiology] | In a significant change of policy towards ‘designer babies’, the UK Human Fertilisation and Embryology Authority approves tissue-matching tests on embryos for the purposes of saving the life of a sick older brother or sister. |
