On April 4:
1081 Alexios I Komnenos was crowned Byzantine emperor at Constantinople, beginning the Komnenian dynasty.
1581 Francis Drake was knighted for completing a circumnavigation of the world.
1655 The the Infant of Prague statue was solemnly crowned by command of Cardinal Harrach.
1660 Declaration of Breda by King Charles II of England.
1721 Sir Robert Walpole became the first Prime Minister of the United Kingdom under King George I.
1802 Dorothea Dix, American social activist, was born.
1812 U.S. President James Madison enacted a ninety-day embargo on trade with the United Kingdom.
1814 Napoleon abdicated for the first time.
1818 The United States Congress adopted the flag of the United States with 13 red and white stripes and one star for each state (then 20).
1841 William Henry Harrison died of pneumonia becoming the first President of the United States to die in office and the one with the shortest term served.
1850 The Great Fire of Cottenham, a large part of the Cambridgeshire village was burnt to the ground under suspicious circumstances.
1850 – Los Angeles was incorporated as a city.
1873 The Kennel Club was founded, the oldest and first official registry of purebred dogs in the world.
1887 Argonia, Kansas elected Susanna M. Salter as the first female mayor in the United States.
1905 The Kangra earthquake killed 20,000, and destroyed most buildings in Kangra, Mcleodganj and Dharamshala.
1913 The Greek aviator Emmanuel Argyropoulos becomes the first pilot victim of the Hellenic Air Force when his plane crashed.
1930 The Communist Party of Panama was founded.
1939 Faisal II became King of Iraq.
1944 World War II: First bombardment of Bucharest by Anglo-American forces killed 3000 civilians.
1945 World War II: American troops liberated Ohrdruf forced labour camp in Germany.
1945 – World War II: Soviet Army took control of Hungary.
1949 Twelve nations signed the North Atlantic Treaty creating the North Atlantic Treaty Organisation.
1949 Junior Braithwaite, Jamaican singer (The Wailers), was born.
1951 Hun Sen, Prime Minister of Cambodia, was born.
1958 The CND Peace Symbol displayed in public for the first time in London.
1960 Senegal independence day.
1963 Graham Norton, Irish talk show host, was born.
1965 The first model of the new Saab Viggen fighter aircraftplane was 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. was assassinated by James Earl Ray.
1968 – Apollo programme: NASA launched Apollo 6.
1968 – AEK Athens BC became the first Greek team to win the European Basketball Cup.
1969 Dr. Denton Cooley implanted the first temporary artificial heart.
1973 The World Trade Center in New York was officially dedicated.
1975 Vietnam War: Operation Baby Lift – A United States Air Force C-5A Galaxy crashed near Saigon shortly after takeoff, transporting orphans – 172 died.
1976 Prince Norodom Sihanouk resignws as leader of Cambodia and was placed under house arrest.
1979 Heath Ledger, Australian actor, was born.
1979 Jessica Napier, New Zealand actress, was born.
1979 President Zulfikar Ali Bhutto of Pakistan was executed.
1983 Space Shuttle Challenger made its maiden voyage into space (STS-6).
1984 President Ronald Reagan called for an international ban on chemical weapons.
1991 Senator John Heinz and six others were killed when a helicopter collidds with their plane over an elementary school in Merion, Pennsylvania.
2001 Dame Silvia Cartwright became Governor General of New Zealand.
2002 The Angolan government and UNITA rebels signed a peace treaty ending the Angolan Civil War.
2007 15 British Royal Navy personnel held in Iran were released by the Iranian President.
Sourced from NZ History Online & Wikipedia