| 22 May 337 | Asia Minor [births and deaths] | Constantine I the Great, first Christian Roman emperor of Western empire 312–324, And of whole empire 324–337, dies in Ancyrona, near Nicomedia, in Bithynia, Asia Minor (now Izmit, Turkey) (c. 57). |
| 22 May 1324 | Germany, Holy Roman Empire [political events] | In the Appeal of Sachsenhausen, King Ludwig IV of Bavaria denounces Pope John XXII and denies his claim to temporal authority in Germany. |
| 22 May 1328 | Italy, Holy Roman Empire [administration] | Having deposed Pope John XXII when the Pope declares a crusade against him, King Ludwig IV of Bavaria elects the Italian clergyman Pietro Rainalducci (Peter of Corvara) as the antipope Nicholas V. |
| 22 May 1455 | England [Wars of the Roses (1455–85)] | The Wars of the Roses begin when forces under Richard, Duke of York, and the Neville earls of Warwick and Salisbury are refused a parley and rapidly defeat the armies of King Henry VI of England in St Albans, England. The king's commander, the Duke of Somerset, is killed, and the king is wounded and captured. |
| 22 May 1545 | India, Mogul Empire [political events] | Sher Khan, conqueror of the Mogul ruler Humayun, is killed after a reign dominated by economic and administrative reform, at the siege of Kalinjar, on the road south from the River Ganges. |
| 22 May 1629 | Denmark-Norway, Holy Roman Empire [treaties] | King Christian IV of Denmark and Norway is forced to sign the Peace of Lübeck with the Holy Roman Emperor Ferdinand II, following his defeat by Albrecht von Wallenstein, the imperial commander in chief. Christian undertakes to refrain from intervening in imperial affairs. |
| 22 May 1670 | UK, France [treaties] | The secret Treaty of Dover between Britain and France is signed. King Charles II of England promises to declare himself a Catholic in return for a subsidy. He also engages to support King Louis XIV of France against Spain and to provide naval assistance in a joint war against the United Netherlands. |
| 22 May 1762 | Sweden, Prussia [treaties] | The Treaty of Hamburg ends hostilities between Sweden and Prussia, restoring all conquests made during the Seven Years' War. |
| 22 May 1810 | New Granada, Spain [political events] | A revolt breaks out in the Spanish viceroyalty of New Granada against Spanish authority. |
| 22 May 1813 | Germany [births and deaths] | (Wilhelm) Richard Wagner, German dramatic composer and theorist who writes the operatic sequence Der Ring des Nibelungen/The Ring of the Nibelung, born in Leipzig, Germany (–1883). |
| 22 May 1833 | Chile [law and government] | A constitution in Chile ends internal unrest and creates an oligarchic, conservative regime, giving greater power to the president and establishing Roman Catholicism as the state religion. |
| 22 May 1859 | Scotland [births and deaths] | Arthur Conan Doyle, Scottish novelist who creates the detective Sherlock Holmes, born in Edinburgh, Scotland (–1930). |
| 22 May 1907 | [births and deaths] | Laurence Olivier, English stage and film actor, director, and producer, born in Dorking, Surrey, England (–1989). |
| 22 May 1912 | Austria-Hungary [law and government] | Count Stephen Tisza, leader of the Hungarian National Party of Work, is elected president of the Hungarian chamber. Socialists call a strike in support of universal male suffrage and riots occur in Budapest, Austria-Hungary. |
| 22 May 1939 | Germany, Italy [treaties] | The German Führer and Italian prime minister sign a ten-year political and military alliance, the ‘Pact of Steel’. |
| 22–25 May 1963 | Africa [international organizations] | The Organization of African Unity (OAU; later African Union) is founded at a conference of African leaders in Addis Ababa, Ethiopia; it aims to maintain solidarity between African leaders and remove colonialism from the African continent. |
| 22–30 May 1972 | USSR, USA [diplomacy] | Richard Nixon becomes the first US president to visit the USSR. On 26 May he signs a treaty limiting antiballistic missile sites. |
| 22 May 1972 | Ceylon [political events] | Ceylon ceases to be a British dominion and becomes a republic within the Commonwealth under the name of Sri Lanka. |
| 22 May 1990 | North Yemen, South Yemen,Yemen [diplomacy] | The traditionally antagonistic North and South Yemen merge to form the Yemen Republic. |
| 22–31 May 2003 | Iraq [Second Gulf War (2003)] | Contrasting with the deep divisions in the United Nations (UN) Security Council in the run-up to the US-led war in Iraq against the regime of Saddam Hussein, the 15-member body adopts a new resolution (by 14 votes to 0, with Syria not participating) granting wide interim governing powers over Iraq to the USA, including a role for a UN special representative, and lifting sanctions imposed on Iraq almost 13 years ago following the invasion of Kuwait. As the month ends, the failure to unearth conclusive evidence of Iraqi weapons of mass destruction leads to increasing criticism of the US and UK's case for going to war. |
| 22 May 2006 | England [surgery] | A pioneering form of heart transplant, in which the donor heart is kept beating while it is transported to the patient, is carried out for the first time in Britain at a hospital in Cambridge, England. |
