Old clock in sand with the words: It Happend in May

Browse Historical Events by Day: What Happened on May 11th?

Discover major events and cultural milestones that happened on this day — organized by year. Dates for earlier events may be approximate.

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330 CE, May 11

Byzantium was renamed Constantinople (now Istanbul) and dedicated to Emperor Constantine. Constantinople is generally considered to be the center and the "cradle of Orthodox Christian civilization". Constantinople was the largest and wealthiest city in Europe, from the mid-5th century to the early 13th century.

1189 CE, May 11

Holy Roman Emperor Frederick I Barbarossa and 100,000 crusaders depart Regensburg for the Third Crusade which is also known as the Kings's Crusade. It was an attempt led by three European monarchs of Western Christianity (Philip II of France, Richard I of England and Frederick I, Holy Roman Emperor) to reconquer the Holy Land following the capture of Jerusalem by the Ayyubid sultan Saladin in 1187. It recaptured the important cities of Acre and Jaffa, and reversed most of Saladin's conquests, but it failed to recapture Jerusalem. .

1751 CE, May 11

Pennsylvania Hospital, the nation's first hospital, is founded by Benjamin Franklin and Dr. Thomas Bond.

1858 CE, May 11

Minnesota is admitted to the Union and becomes the 32nd State.

1934 CE, May 11

An enormous dust storm, 1,500 miles long and 600 miles wide, that originated on the west coast, moved eastward across the Great Plains. A total of 300 million tons of topsoil, parched to dust by drought were blown out of the Great Plains. More

Image by Rev. W.J. Commanghlon

1995 CE, May 11

More than 170 countries agree to extend the Nuclear Nonproliferation Treaty (NPT) indefinitely and without conditions to prevent the spread of nuclear weapons. A total of 191 States have now joined the Treaty, including the five nuclear-weapon States More