Browse Historical Events by Day: What Happened on December 12th?

Pennsylvania ratifies the Constitution of the United States becoming the second State of the Union.

Guglielmo Marconi and his assistant, George Kemp, confirmed the reception of the first transatlantic radio signals from their test site in St. John, Newfoundland and Labrador, Canada. With a telephone receiver and a wire antenna kept aloft by a kite, they heard Morse code for the letter "S" transmitted from Poldhu, Cornwall, England. Their experiments showed that radio signals extended far beyond the horizon, giving radio a new global dimension for communication in the twentieth century. More

The stolen “Mona Lisa” was recovered in Florence, Italy. The thief, Vincenzo Perugia, was arrested. He claimed he was avenging Italy. More

Kenya becomes fully independent from British rule. A year later, Kenya became a republic (with Kenyatta as its first president and Oginga Odinga as vice president). More

Leonardo Da Vinci's manuscript known as the Leicester Codex is sold in auction to American oil tycoon Armand Hammer for $5.1M . The manuscript written circa 1508, contained 72 loose pages with over 300 notes and drawings. Thomas Coke, the first earl of Leicester, bought the manuscript in 1717 and installed it among his impressive collection of art at his family estate in England. The manuscript was placed in auction by the then current Earl of Leicester. Hammer placed it in his private art collection. In 1994 it was bought by Bull Gates for $30.8M. More

The United States Supreme Court releases its 5-4 decision in the case of Bush v. Gore with Justice Sandra Day O’Connor providing the "swing vote". The Court decision effectively ended the Florida recount of the presidential election and lead to the election of George W. Bush as President of the United States. Bob Gore won the popular vote by 537,179 votes but Bush won 271 Electoral votes versus 266 for Gore, who conceded the following day. More

The Paris Agreement on climate change is adopted by 196 countries during the COP21 summit.