April 20 – On this Day in History

This article delves into notable historical events that occurred on April 20th, arranged in chronological order.

From pivotal political decisions and groundbreaking scientific achievements to dramatic social movements and profound cultural shifts, each event offers a window into the complexities of human history.

By exploring these diverse occurrences, we gain insights into the forces that have shaped our world across various spheres—including politics, science, culture, and society.

Through this exploration, we not only commemorate these moments but also reflect on their enduring impact on contemporary life.

April 20th Events in History

1303 – The Sapienza University of Rome is instituted by Pope Boniface VIII

The Sapienza University of Rome, often referred to simply as “La Sapienza,” was founded by Pope Boniface VIII via the papal bull “In Supremae Praeeminentia Dignitatis.”

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It was established to offer free education to students in theology, canon law, and eventually in medicine and philosophy.

Over the centuries, it has grown to become one of Europe’s largest universities by enrollment and has been influential in academic, scientific, and cultural developments.

1534 – Jacques Cartier begins his first voyage to what is today the east coast of Canada, Newfoundland, and Labrador

Jacques Cartier, a French explorer, embarked on his first voyage in April 1534, with the objective of finding a westward route to Asia. Instead, he explored parts of what are now known as Newfoundland and Labrador, claiming the land for the King of France.

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His journey opened the way for French exploration of North America, and he is credited with naming “Canada,” derived from the Iroquoian word “kanata,” meaning village or settlement.

Jacques Cartier

1653 – Oliver Cromwell dissolves the Rump Parliament in England

On April 20, 1653, Oliver Cromwell, a political and military leader during the English Civil War, dissolved the Rump Parliament.

This Parliament had been in power since the execution of King Charles I in January 1649, but Cromwell was dissatisfied with its progress and its leaning toward radical reforms.

He entered the House of Commons and forcibly ejected the members, setting the stage for his own rule as Lord Protector under a different constitutional framework.

1657 – Freedom of religion is granted to the Jews of New Amsterdam (later New York City)

In 1657, the Jews living in New Amsterdam, a Dutch colonial settlement that later became New York City, were granted the right to worship freely. This was significant because, at the time, religious tolerance was rare in many parts of the world.

The policy reflected the relatively liberal attitudes of the Dutch toward different religions and cultures, which influenced the developing social fabric of what would become a major American city.

1775 – American Revolutionary War: The Siege of Boston begins, following the battles at Lexington and Concord

The Siege of Boston began shortly after the initial conflicts of the American Revolutionary War at Lexington and Concord on April 19, 1775. Following these clashes, American militiamen surrounded Boston to prevent the British Army, stationed there, from making further advances.

The siege lasted until March 1776, when British forces were compelled to evacuate the city after the Americans fortified Dorchester Heights with cannons captured from Fort Ticonderoga, a strategic move largely orchestrated by George Washington.

1792 – France declares war on Austria, marking the start of the French Revolutionary Wars

On April 20, 1792, the French Legislative Assembly voted to declare war on Austria, initiating the French Revolutionary Wars.

This decision came amidst rising revolutionary fervor and suspicion of King Louis XVI’s loyalties, as many believed he harbored sympathies for Austria, partly because his wife, Marie Antoinette, was Austrian.

The declaration of war marked France’s first offensive action in what would evolve into a broader conflict involving multiple European powers, reshaping the continent’s political landscape.

Napoleon at The Battle of Austerlitz

1809 – Two battles of the War of the Fifth Coalition occur: the Battle of Abensberg and the Battle of Eckmühl

During the War of the Fifth Coalition against Napoleon, two significant battles occurred around April 20, 1809. The Battle of Abensberg took place on April 20th itself, where Napoleon’s forces defeated the Austrians under Archduke Karl.

The victory allowed the French to split the Austrian army into two, weakening their operational capabilities. Shortly after, the Battle of Eckmühl on April 22nd furthered French success, with Napoleon decisively defeating the Austrians, forcing them to retreat. These victories were crucial in strengthening Napoleon’s grip over the region.

1836 – The Territory of Wisconsin is created by the U.S. Congress

On April 20, 1836, the U.S. Congress established the Territory of Wisconsin as land was being rapidly acquired and settled following the removal of Native American tribes.

The territory comprised areas that would later become the states of Wisconsin, Minnesota, and parts of the Dakotas. This act was part of the broader westward expansion of the United States and reflected the growing American ambition to settle the western frontiers.

1861 – Robert E. Lee resigns from the United States Army in order to command the forces of the state of Virginia

On April 20, 1861, in the early days of the American Civil War, Robert E. Lee made the momentous decision to resign from his position as a colonel in the United States Army.

Following Virginia’s decision to secede from the Union, Lee chose to align with his home state, despite having been offered command of the entire Union Army.

His resignation was a significant event, as Lee went on to become the commanding general of the Confederate Army, playing a crucial role in the war’s proceeding conflicts.

1862 – Louis Pasteur and Claude Bernard complete the experiment disproving the theory of spontaneous generation

Louis Pasteur, together with his colleague Claude Bernard, conducted a pivotal experiment on April 20, 1862, that challenged and ultimately disproved the theory of spontaneous generation—the belief that life could arise from non-living matter. Pasteur’s experiment involved boiling broth in swan-neck flasks.

The unique shape of the flasks prevented airborne microorganisms from contaminating the broth, demonstrating that microbial life did not spontaneously generate but originated from existing microorganisms. This experiment was foundational in the development of microbiology and modern germ theory.

1871 – The Civil Rights Act of 1871 becomes law in the United States

Also known as the Ku Klux Klan Act, the Civil Rights Act of 1871 was signed into law on April 20, 1871, by President Ulysses S. Grant.

The act was primarily aimed at protecting the civil rights of African Americans in the Southern United States during the Reconstruction Era, following the Civil War.

It allowed the federal government to intervene in states where conspiracies to deny citizens’ constitutional rights were rampant, particularly targeting the actions of the Ku Klux Klan. This legislation was crucial in enforcing the 14th Amendment and combating racial violence.

1884 – Pope Leo XIII publishes the encyclical “Humanum Genus”

On April 20, 1884, Pope Leo XIII issued the encyclical “Humanum Genus,” which addressed the condition of the human race from a Catholic perspective. The document was primarily a condemnation of Freemasonry and other secular influences that the Pope considered to be detrimental to the faith.

It delineated a worldview split between two opposing camps: the kingdom of God and the kingdom of Satan, urging Catholics to resist secular trends and uphold Christian values.

1902 – Pierre and Marie Curie refine radium chloride

On this date, Pierre and Marie Curie successfully isolated radium as radium chloride, marking a significant milestone in the field of radioactivity—a term which Marie herself coined.

This achievement followed their discovery of the element in 1898 while investigating the radioactive properties of pitchblende. The isolation of radium was crucial for further experiments and applications in both medicine and industry, solidifying the Curies’ legacy in the scientific community.

1912 – Opening day for baseball’s Tiger Stadium in Detroit and Fenway Park in Boston

April 20, 1912, was a landmark day in American sports history with the opening of two iconic baseball stadiums. Tiger Stadium in Detroit and Fenway Park in Boston both hosted their first games on this day. Fenway Park, home of the Boston Red Sox, is especially renowned for its “Green Monster,” a high left-field wall.

Tiger Stadium, which was home to the Detroit Tigers until 1999, was beloved for its intimate setting and unique dimensions. Both parks have played significant roles in the cultural and sporting life of their respective cities.

1914 – The Ludlow Massacre during the Colorado Coalfield War results in the deaths of about 20, including women and children

The Ludlow Massacre was a tragic and pivotal event in American labor history, occurring on April 20, 1914. During a prolonged strike by coal miners against poor working conditions, low wages, and company control of miners’ lives in southern Colorado, tensions escalated between striking miners and the Colorado National Guard.

The confrontation reached its peak at the Ludlow tent colony, where the National Guard attacked, resulting in the deaths of roughly 20 people, including miners’ wives and children.

This event highlighted the extreme measures some employers and governmental bodies would use against labor movements and led to significant national outcry and subsequent labor reforms.

1918 – Manfred von Richthofen, also known as the “Red Baron,” is shot down and killed over Vaux-sur-Somme in France

Manfred von Richthofen, better known as the “Red Baron,” was a celebrated German fighter pilot during World War I, credited with 80 air combat victories. On April 20, 1918, he was killed in aerial combat over Vaux-sur-Somme, France.

Richthofen was flying his Fokker Dr.I triplane and was pursuing a Canadian pilot across enemy lines when he was shot. Although there is some debate over who fired the fatal shot, it is most commonly believed that he was hit by ground fire from Australian troops.

His death marked the end of a legendary flying career and he remains one of the most famous aviators in history.

1945 – World War II: U.S. troops capture Leipzig, Germany, only to later cede the city to the Soviet Union

During the final days of World War II in Europe, American forces successfully captured Leipzig, Germany, on April 20, 1945, after intense urban combat.

However, following the Yalta Agreement, where Allied leaders decided upon the post-war division of Germany, Leipzig fell within the Soviet occupation zone. Consequently, American troops withdrew from the city in early July 1945, handing control over to the Soviet Union.

This was part of the broader realignment and occupation of Germany that set the stage for the Cold War.

1968 – English politician Enoch Powell makes his controversial “Rivers of Blood” speech

Enoch Powell, a member of the Conservative Party and a Member of Parliament, delivered a highly controversial speech on April 20, 1968, which became known as the “Rivers of Blood” speech.

Speaking to a Conservative Association meeting in Birmingham, Powell criticized mass immigration from the Commonwealth nations and expressed his grave concerns about the future societal impacts in Britain.

The speech sparked a huge political and public backlash, leading to Powell’s removal from his position in the Shadow Cabinet. The speech remains one of the most polarizing moments in British political history, reflecting deep-seated tensions about race and identity.

1999 – The Columbine High School massacre takes place in Columbine, Colorado

On April 20, 1999, one of the most tragic school shootings in American history occurred at Columbine High School in Colorado.

Two students, Eric Harris and Dylan Klebold, embarked on a shooting spree that killed 12 students and one teacher, and wounded more than 20 others, before taking their own lives.

The massacre shocked the nation and significantly influenced national discourse on gun control laws, school safety protocols, and the cultural treatment of adolescent mental health.

2010 – The Deepwater Horizon drilling rig explodes in the Gulf of Mexico, starting an environmental disaster

The Deepwater Horizon, an offshore drilling rig, exploded on April 20, 2010, resulting in one of the worst environmental disasters in U.S. history. The explosion killed 11 workers and led to a massive oil spill in the Gulf of Mexico, releasing approximately 4.9 million barrels of oil into the water.

The spill had devastating effects on marine and wildlife habitats and the local fishing and tourism industries. This incident sparked a widespread environmental campaign against offshore drilling and led to significant legal and regulatory changes in the oil and gas industry.