| 27 March 1188 | Holy Roman Empire, Saxony, Bavaria, Germany [Crusades (1095–1272)] | The Holy Roman Emperor Frederick I Barbarossa takes the Cross (agrees to go on crusade); by his order Henry the Lion, the dispossessed Duke of Saxony and Bavaria, goes back into exile. |
| 27 March 1351 | France, England [Hundred Years War (1337–1453)] | The ‘Battle of the Thirty’ is fought between thirty English champions and the same number of Bretons and others of the Montfort party, in an attempt to end the dispute over the occupancy of the duchy of Brittany. The English party lose. |
| 27 March 1625 | UK [political events] | Prince Charles becomes King Charles I of England, Ireland, and Scotland on the death of his father James I of England and Ireland (usually described as James I of England) and VI of Scotland. |
| 27 March 1625 | Scotland, England [births and deaths] | James VI of Scotland (1567–1625) and I of England (1603–1625), son of Mary Queen of Scots, dies in Theobalds, Hertfordshire, England (58). |
| 27 March 1721 | Spain, France [treaties] | The Treaty of Madrid, a treaty of mutual defence and guarantee, is signed between France and Spain. France promises to assist in the restoration of Gibraltar, captured from Spain by the British in 1704 and confirmed as a British possession by the Treaty of Utrecht, and in the regulation in Spain's favour of questions concerning claims to the Italian duchies of Parma, Naples, and Sicily. |
| 27 March 1802 | UK, France, Europe [treaties] | The Treaty of Amiens is signed between Britain and France, based on the preliminaries agreed on 1 October 1801; it achieves (briefly) the complete pacification of Europe. |
| 27 March 1920 | Russia [Russian Civil War (1918–20)] | The Red Army takes Novorossiysk on the Black Sea, precipitating the collapse of Anton Denikin's White Russian army. General Peter Wrangel takes command of White operations. |
| 27 March 1941 | Yugoslavia [revolution] | Prince Paul, Regent of Yugoslavia, is deposed in a coup organized by air force officers exploiting the unpopularity of adherence to the Tripartite Pact between the Axis powers (Germany, Italy, and Japan). |
| 27 March 1964 | USA [natural disasters] | An earthquake measuring between 8.3 and 8.5 (later amended upward) on the Richter scale strikes Anchorage in Alaska. Although the sparse population limits casualties to 131, it is the most severe earthquake ever recorded in North America. An area of 120,000 sq km/75,000 sq mi is tilted and in some places adjacent sections of land are separated by 25 m/82 ft. |
| 27 March 1968 | USSR [births and deaths] | Yuri Gagarin, Soviet cosmonaut and the first person to travel in space, is killed when his jet aircraft crashes near Moscow, USSR (34). |
| 27 March 1998 | USA [medicine] | The US manufacturing company Pfizer gets approval from the US Food and Drug Administration (FDA) for its pill Viagra, which can cure male impotence. It becomes the fastest-selling prescription drug in US history. |
| 27 March 2007 | world [medicine] | Scientists announce the world's first case of semi-identical human twins. |
