| 30 June 1109 | Castile, León, Aragon, Navarre, Spain [administration] | King Alfonso VI of Castile and León dies; he is succeeded by his daughter Urracca, the wife of King Alfonso I of Aragon and Navarre, who begins to style himself ‘Emperor of the Spains’. |
| 30 June 1520 | Mexico, Aztec Empire, Spain [colonization] | The Spanish conquistador Hernán Cortés returns, reinforced, to the Aztec capital of Tenochtitlán in the Valley of Mexico to find the force he left behind under Pedro de Alvarado besieged by Aztecs under Cuitlahuoc, following Alvarez's murder of Cuitlahuoc's predecessor, the Aztec emperor Montezuma II. The Spaniards break in and out, losing a third of their army in ‘the Bloody Night’ as they escape the city. |
| 30 June 1652 | United Netherlands, UK [Anglo–Dutch Wars (1652–74)] | After a period of growing tension, triggered by the passing of the first Navigation Act, England declares war on the United Netherlands. |
| 30 June 1685 | England [births and deaths] | John Gay, English poet and dramatist, author of The Beggar's Opera (1728), born in Barnstaple, Devonshire, England (–1732). |
| 30 June 1734 | Russia, Poland [War of the Polish Succession (1733–38)] | In the War of the Polish Succession, Russian troops take the Polish city of Danzig (modern Gdansk), which has been besieged by them since October 1733. Danzig is captured after the failure of a French expedition to relieve the city. |
| 30 June 1852 | UK, New Zealand [law and government] | A British act of Parliament grants a new constitution providing for representative government for the colony of New Zealand. |
| 30 June 1859 | France, USA, Canada [sports] | The French tightrope walker Charles Blondin (pseudonym of Jean-François Gravelet) crosses Niagara Falls, between Canada and the USA, on a tightrope. About 25,000 people witness the crossing, which takes five minutes. |
| 30 June 1860 | UK [Christianity] | At the British Association for the Advancement of Science meeting in Oxford, Darwin's theory of evolution is widely discussed, especially its implications for the origin of humans among apes. Conservative English cleric Archbishop Samuel Wilberforce joins forces with scientists opposed to Darwin's theories. English biologist Thomas Henry Huxley aggressively defends Darwin, earning the reputation of his ‘bulldog’. is an important advocate of his friend Darwin's theory of evolution through natural selection. |
| 30 June 1861 | England, Florence [births and deaths] | Elizabeth Barrett Browning, English poet and wife of the English poet Robert Browning, dies in Florence, Italy (55). |
| 30 June 1876 | Serbia, Ottoman Empire [wars] | Serbia, under the nationalist leader Jovan Ristic, declares war on the Ottoman Empire. |
| 30 June 1908 | Russian Empire [natural disasters] | An aerial explosion equivalent to 10–15 megatons of TNT flattens approximately 2,000 sq km/1,243 mi of forest near the Tunguska River, Siberia, Russian Empire. No meteorite fragments are discovered but it is thought to have been a fragment of a comet disintegrating in the atmosphere. |
| 30 June 1934 | Germany [political events] | The German chancellor, Adolf Hitler, purges the SA (Sturmabteilung, storm troopers or ‘Brownshirts’) of dozens of its top leaders in the ‘Night of the Long Knives’. Those murdered by Heinrich Himmler's SS (Schutzstaffel, Nazi elite corps) as potential rivals to Hitler include the SA head Ernst Röhm and the former chancellor Kurt von Schleicher. |
| 30 June 1960 | South Africa [legislation] | The Promotion of Bantu Self-Government Act comes into force in South Africa, establishing separate ‘homelands’ for blacks. |
| 30 June 1967 | world [treaties] | Forty-six nations sign the Final Acts of the ‘Kennedy round’ of the General Agreement on Tariffs and Trade (GATT). |
| 30 June 1977 | Asia [political events] | The Southeast Asia Treaty Organization (SEATO), a collective military system, is dissolved. |
