April 4 events in history

1147 First historical record of Moscow
1287 King Wareru founds Kingdom of Ramannadesa, and proclaims independence from Pagan Empire
1581 Francis Drake is knighted for completing a circumnavigation of the world
1660 Declaration of Breda by King Charles II of England
1721 Sir Robert Walpole takes office as the first Prime Minister of the United Kingdom under King George I
1768 In London, Philip Astley stages the first modern circus
1796 Georges Cuvier delivers his first paleontological lecture at École Centrale du Pantheon of the Muséum national d'histoire naturelle on living and fossil remains of elephants and related species, founding the science of Paleontology
1812 U.S. President James Madison enacts a ninety-day embargo on trade with the United Kingdom
1814 Napoleon abdicates for the first time and names his son Napoleon II as Emperor of the French
1818 The United States Congress adopts the flag of the United States with 13 red and white stripes and one star for each state (then 20)
1841 William Henry Harrison dies of pneumonia becoming the first President of the United States to die in office and with the shortest term served
1850 The Great Fire of Cottenham: a large part of the Cambridgeshire village (England) is burnt to the ground in suspicious circumstances
1850 Los Angeles, California, is incorporated as a city
1859 Bryant's Minstrels debut "Dixie" in New York City in the finale of a blackface minstrel show
1865 American Civil War: A day after Union forces capture Richmond, Virginia, U.S. President Abraham Lincoln visits the Confederate capital
1866 Alexander II of Russia narrowly escapes an assassination attempt by Dmitry Karakozov in the city of Saint Petersburg
1873 The Kennel Club is founded, the oldest and first official registry of purebred dogs in the world
1887 Argonia, Kansas elects Susanna M. Salter as the first female mayor in the United States
1905 In India, an earthquake hits the Kangra Valley, killing 20,000, and destroying most buildings in Kangra, Mcleodganj and Dharamshala
1913 First Balkan War: Greek aviator Emmanouil Argyropoulos becomes the first pilot to die in the Hellenic Air Force when his plane crashes
1930 The Communist Party of Panama is founded
1933 U.S. Navy airship, USS Akron, is wrecked off the New Jersey coast due to severe weather
1939 Faisal II becomes King of Iraq
1944 World War II: First bombardment of oil refineries in Bucharest by Anglo-American forces kills 3000 civilians
1945 World War II: American troops liberate Ohrdruf forced labor camp in Germany
1945 World War II: American troops capture Kassel
1949 Twelve nations sign the North Atlantic Treaty creating the North Atlantic Treaty Organization
1958 The CND peace symbol is displayed in public for the first time in London
1960 France agrees to grant independence to the Mali Federation, a union of Senegal and French Sudan
1964 The Beatles occupy the top five positions on the Billboard Hot 100 pop chart
1965 The first model of the new Saab Viggen fighter aircraft is unveiled
1967 Martin Luther King, Jr. delivers his "Beyond Vietnam: A Time to Break Silence" speech in New York City's Riverside Church
1968 Martin Luther King, Jr. is assassinated by James Earl Ray at a motel in Memphis, Tennessee
1968 Apollo program: NASA launches Apollo 6
1968 AEK Athens BC becomes the first Greek team to win the European Basketball Cup
1969 Dr. Denton Cooley implants the first temporary artificial heart
1973 The World Trade Center in New York is officially dedicated
1973 A Lockheed C-141 Starlifter, dubbed the Hanoi Taxi, makes the last flight of Operation Homecoming
1975 Microsoft is founded as a partnership between Bill Gates and Paul Allen in Albuquerque, New Mexico
1975 Vietnam War: Operation Baby Lift – A United States Air Force Lockheed C-5A Galaxy transporting orphans, crashes near Saigon, South Vietnam shortly after takeoff; 172 die
1976 Prince Norodom Sihanouk resigns as leader of Cambodia and is placed under house arrest
1979 Prime Minister Zulfikar Ali Bhutto of Pakistan is executed
1981 The Islamic Republic of Iran Air Force mounts an attack on H-3 Airbase and destroys about 50 Iraqi aircraft
1983 Space Shuttle Challenger makes its maiden voyage into space
1984 President Ronald Reagan calls for an international ban on chemical weapons
1988 Governor Evan Mecham of Arizona is convicted in his impeachment trial and removed from office
1991 Senator John Heinz of Pennsylvania and six others are killed when a helicopter collides with their airplane over an elementary school in Merion, Pennsylvania
1991 The current flag of Hong Kong is adopted for post-colonial Hong Kong during the Third Session of the Seventh National People's Congress
1994 Marc Andreessen and Jim Clark found Netscape Communications Corporation under the name "Mosaic Communications Corporation"
1996 Comet Hyakutake is imaged by the USA Asteroid Orbiter Near Earth Asteroid Rendezvous