August 4
- 1265 - The Battle of Evesham of the Second Barons' War is fought in Worcestershire, with the army of future King Edward I of England defeating the forces of rebellious barons led by Simon de Montfort, 6th Earl of Leicester and killing de Montfort and many of his allies. This is sometimes considered the death of chivalry in England.
- 1578 - Battle of Al Kasr al Kebir - Moroccans defeat Portuguese. King Sebastian of Portugal is defeated and killed in North Africa, leaving his elderly uncle, Cardinal Henry, as his heir. This initiates a succession crisis in Portugal.
- 1704 - During the War of the Spanish Succession an Anglo-Dutch force seizes the rock of Gibraltar.
- 1824 - Battle of Cos fought between Turks and Greeks.
- 1873 - Indian Wars: While protecting a railroad survey party in Montana, the United States 7th Cavalry, under Lieutenant Colonel George Armstrong Custer, clash for the first time with the Sioux (near the Tongue River; only one man on each side is killed).
- 1914 - World War I: Germany invaded Belgium; in response, the United Kingdom declares war on Germany. The United States proclaims neutrality.
August 4
- 1265 - The Battle of Evesham of the Second Barons' War is fought in Worcestershire, with the army of future King Edward I of England defeating the forces of rebellious barons led by Simon de Montfort, 6th Earl of Leicester and killing de Montfort and many of his allies. This is sometimes considered the death of chivalry in England.
- 1578 - Battle of Al Kasr al Kebir - Moroccans defeat Portuguese. King Sebastian of Portugal is defeated and killed in North Africa, leaving his elderly uncle, Cardinal Henry, as his heir. This initiates a succession crisis in Portugal.
- 1704 - During the War of the Spanish Succession an Anglo-Dutch force seizes the rock of Gibraltar.
- 1824 - Battle of Cos fought between Turks and Greeks.
- 1873 - Indian Wars: While protecting a railroad survey party in Montana, the United States 7th Cavalry, under Lieutenant Colonel George Armstrong Custer, clash for the first time with the Sioux (near the Tongue River; only one man on each side is killed).
- 1914 - World War I: Germany invaded Belgium; in response, the United Kingdom declares war on Germany. The United States proclaims neutrality.