The Diocletianic Persecution of Christians in the Roman Empire ends.

Diocletianic PersecutionRoman Empire

Battle of Tzirallum: Emperor Licinius defeats Maximinus II and unifies the Eastern Roman Empire.

Battle of TzirallumLiciniusMaximinus IIEastern Roman Empire

Chindasuinth is proclaimed king by the Visigothic nobility and bishops.

ChindasuinthVisigoths

Enguerrand de Marigny is hanged at the instigation of Charles, Count of Valois.

Enguerrand de MarignyCharles, Count of Valois

Spain gives Christopher Columbus his commission of exploration.

Christopher Columbus

Edmund de la Pole, Yorkist pretender to the English throne, is executed on the orders of Henry VIII.

Edmund de la Pole, 3rd Duke of SuffolkHenry VIII of England

Mapuche leader Lautaro is killed by Spanish forces at the Battle of Mataquito in Chile.

MapucheLautaroSpanish EmpireBattle of MataquitoChile

Juan de Oñate makes a formal declaration of his Conquest of New Mexico.

Juan de Oñate

Henry IV of France issues the Edict of Nantes, allowing freedom of religion to the Huguenots.

Henry IV of FranceEdict of NantesFreedom of religionHuguenot

Eighty Years' War: Dutch Republic forces recapture a strategically important fort from Spain after a nine-month siege.

Eighty Years' WarDutch RepublicSiege of Schenkenschans

Petar Zrinski, the Croatian Ban from the Zrinski family, is executed.

Petar ZrinskiCroatiaBan (title)ZrinskiCapital punishment

On the balcony of Federal Hall on Wall Street in New York City, George Washington takes the oath of office to become the first elected President of the United States.

Federal HallWall StreetGeorge WashingtonFirst inauguration of George WashingtonPresident of the United States

Louisiana Purchase: The United States purchases the Louisiana Territory from France for $15 million, more than doubling the size of the young nation.

Louisiana PurchaseLouisiana Territory

The Territory of Orleans becomes the 18th U.S. state under the name Louisiana.

Territory of OrleansU.S. stateLouisiana

Nicaragua declares independence from the Central American Federation.

NicaraguaCentral American Federation

A 65-man French Foreign Legion infantry patrol fights a force of nearly 2,000 Mexican soldiers to nearly the last man in Hacienda Camarón, Mexico.

French Foreign LegionBattle of Camarón

The Camp Grant massacre takes place in Arizona Territory.

Camp Grant massacreArizona Territory

Governor of New York David B. Hill signs legislation creating the Niagara Reservation, New York's first state park, ensuring that Niagara Falls will not be devoted solely to industrial and commercial use.

Governor of New YorkDavid B. HillNiagara Reservation State ParkNiagara Falls

J. J. Thomson of the Cavendish Laboratory announces his discovery of the electron as a subatomic particle, over 1,800 times smaller than a proton (in the atomic nucleus), at a lecture at the Royal Institution in London.[1]

J. J. ThomsonCavendish LaboratoryElectronSubatomic particleProton

Hawaii becomes a territory of the United States, with Sanford B. Dole as governor.

Sanford B. DoleGovernor of Hawaii

The Louisiana Purchase Exposition World's Fair opens in St. Louis, Missouri.

Louisiana Purchase ExpositionWorld's FairSt. Louis, Missouri

Albert Einstein writes his thesis Eine neue Bestimmung der Moleküldimensionen ("A New Determination of Molecular Dimensions").

Albert Einstein

Honolulu, Hawaii becomes an independent city.

Honolulu, Hawaii

Automaker Dodge Brothers, Inc is sold to Dillon, Read & Co. for US$146 million plus $50 million for charity.

Dodge Brothers, IncDillon, Read & Co.

The Federal Industrial Institute for Women opens in Alderson, West Virginia, as the first women's federal prison in the United States.

Federal Industrial Institute for WomenAlderson, West Virginia

Douglas Fairbanks and Mary Pickford become the first celebrities to leave their footprints in concrete at Grauman's Chinese Theater in Hollywood.

Douglas FairbanksMary PickfordGrauman's Chinese TheaterHollywood

The Commonwealth of the Philippines holds a plebiscite for Filipino women on whether they should be extended the right to suffrage; over 90% would vote in the affirmative.

Commonwealth of the PhilippinesPhilippine women's suffrage plebiscite, 1937

The animated cartoon short Porky's Hare Hunt debuts in movie theaters, introducing Happy Rabbit (a prototype of Bugs Bunny).

Animated cartoonPorky's Hare HuntHappy RabbitEvolution of Bugs Bunny

The 1939-40 New York World's Fair opens.

1939 New York World's Fair

NBC inaugurates its regularly scheduled television service in New York City, broadcasting President Franklin D. Roosevelt's N.Y. World's Fair opening day ceremonial address.

NBCHistory of televisionFranklin D. Roosevelt1939 New York World's Fair