| 84811 | July 27 | Event | 1189 – Friedrich Barbarossa arrives at Niš, the capital of Serbian King Stefan Nemanja, during the Third Crusade. |
| 84812 | July 27 | Event | 1202 – Georgian–Seljuk wars: At the Battle of Basian the Kingdom of Georgia defeats the Sultanate of Rum. |
| 84813 | July 27 | Event | 1214 – Battle of Bouvines: Philip II of France decisively defeats Imperial, English and Flemish armies, effectively ending John of England's Angevin Empire. |
| 84814 | July 27 | Event | 1299 – According to Edward Gibbon, Osman I invades the territory of Nicomedia for the first time, usually considered to be the founding day of the Ottoman state. |
| 84815 | July 27 | Event | 1302 – Battle of Bapheus: Decisive Ottoman victory over the Byzantines opening up Bithynia for Turkish conquest. |
| 84816 | July 27 | Event | 1549 – The Jesuit priest Francis Xavier's ship reaches Japan. |
| 84817 | July 27 | Event | 1663 – The English Parliament passes the second Navigation Act requiring that all goods bound for the American colonies have to be sent in English ships from English ports. |
| 84818 | July 27 | Event | 1689 – Glorious Revolution: The Battle of Killiecrankie ends. |
| 84819 | July 27 | Event | 1694 – A Royal charter is granted to the Bank of England. |
| 84820 | July 27 | Event | 1720 – The Battle of Grengam marks the second important victory of the Russian Navy. |
| 84821 | July 27 | Event | 1778 – American Revolution: First Battle of Ushant: British and French fleets fight to a standoff. |
| 84822 | July 27 | Event | 1789 – The first U.S. federal government agency, the Department of Foreign Affairs, is established (it will be later renamed Department of State). |
| 84823 | July 27 | Event | 1794 – French Revolution: Maximilien Robespierre is arrested after encouraging the execution of more than 17,000 "enemies of the Revolution". |
| 84824 | July 27 | Event | 1862 – Sailing from San Francisco to Panama City, Panama, the SS Golden Gate catches fire and sinks off Manzanillo, Mexico, killing 231. |
| 84825 | July 27 | Event | 1865 – Welsh settlers arrive at Chubut in Argentina. |
| 84826 | July 27 | Event | 1866 – The first permanent transatlantic telegraph cable is successfully completed, stretching from Valentia Island, Ireland, to Heart's Content, Newfoundland. |
| 84827 | July 27 | Event | 1880 – Second Anglo-Afghan War: Battle of Maiwand: Afghan forces led by Mohammad Ayub Khan defeat the British Army in battle near Maiwand, Afghanistan. |
| 84828 | July 27 | Event | 1890 – Vincent van Gogh shoots himself and dies two days later. |
| 84829 | July 27 | Event | 1900 – Kaiser Wilhelm II makes a speech comparing Germans to Huns for years afterwards, "Hun" would be a disparaging name for Germans. |
| 84830 | July 27 | Event | 1914 – Felix Manalo registers the Iglesia ni Cristo with the Philippine government. |
| 84831 | July 27 | Event | 1917 – The Allies reach the Yser Canal at the Battle of Passchendaele. |
| 84832 | July 27 | Event | 1919 – The Chicago Race Riot erupts after a racial incident occurred on a South Side beach, leading to 38 fatalities and 537 injuries over a five-day period. |
| 84833 | July 27 | Event | 1921 – Researchers at the University of Toronto led by biochemist Frederick Banting prove that the hormone insulin regulates blood sugar. |
| 84834 | July 27 | Event | 1929 – The Geneva Convention of 1929, dealing with treatment of prisoners-of-war, is signed by 53 nations. |
| 84835 | July 27 | Event | 1940 – The animated short A Wild Hare is released, introducing the character of Bugs Bunny. |
| 84836 | July 27 | Event | 1941 – Japanese troops occupy French Indochina. |
| 84837 | July 27 | Event | 1942 – World War II: Allied forces successfully halt the final Axis advance into Egypt. |
| 84838 | July 27 | Event | 1949 – Initial flight of the de Havilland Comet, the first jet-powered airliner. |
| 84839 | July 27 | Event | 1953 – Fighting in the Korean War ends when the United States, China, and North Korea sign an armistice agreement. Syngman Rhee, President of South Korea, refuses to sign but pledges to observe the armistice. |
| 84840 | July 27 | Event | 1955 – The Allied occupation of Austria stemming from World War II, ends. |