May 4

Yorkist forces under Edward IV defeat the Lancastrians at the Battle of Tewkesbury, a decisive engagement in England's Wars of the Roses.

Yorkist forces led by King Edward IV decisively defeated the Lancastrian army at the Battle of Tewkesbury, killing the Lancastrian heir Prince Edward and effectively crushing organized Lancastrian resistance during England's Wars of the Roses. The victory secured Edward's hold on the throne for the following decade.

Pope Alexander VI issues the papal bull "Inter caetera," dividing New World territorial claims between Spain and Portugal.

Pope Alexander VI issued the papal bull "Inter caetera," drawing a line of demarcation dividing newly discovered and future New World territories between Spain and Portugal, largely favoring Spanish claims. The decree was later refined by the Treaty of Tordesillas and profoundly shaped the colonial map of the Americas.

Rhode Island becomes the first American colony to formally renounce its allegiance to King George III.

Rhode Island's colonial general assembly voted to formally renounce its allegiance to King George III and struck the king's name from official legal documents and oaths, becoming the first American colony to declare independence from British rule. The vote came two months before the Continental Congress adopted the broader Declaration of Independence, reflecting the colony's longstanding tradition of self-governance and dissent.

Napoleon Bonaparte arrives at Portoferraio on the island of Elba to begin his first exile.

Napoleon Bonaparte arrived at Portoferraio on the small Mediterranean island of Elba to begin his first exile after abdicating the French throne following military defeat by the allied European powers. He would remain there less than a year before escaping and briefly reclaiming power during the Hundred Days.

A bomb is thrown at police during a labor rally in Chicago's Haymarket Square, killing several officers and civilians in the Haymarket affair.

As police attempted to disperse a labor rally in Chicago's Haymarket Square supporting an eight-hour workday, an unknown person threw a bomb into police ranks, triggering gunfire that killed several officers and civilians. The ensuing trial and executions of labor activists made the Haymarket affair a defining, controversial episode in American labor history.

Student demonstrations in Beijing's Tiananmen Square against the Treaty of Versailles's treatment of China spark the May Fourth Movement.

Thousands of Chinese students gathered in Beijing's Tiananmen Square to protest the Treaty of Versailles's decision to transfer former German territorial concessions in China to Japan rather than returning them to Chinese control. The resulting May Fourth Movement galvanized Chinese nationalism and profoundly influenced the country's political and intellectual development.

The United Kingdom's General Strike begins, as workers walk out in support of coal miners facing wage cuts.

Trade unions across the United Kingdom launched a General Strike in solidarity with coal miners facing wage cuts and longer hours, briefly halting much of the country's transportation and industry. The nine-day strike ultimately collapsed without securing the miners' demands, dealing a significant setback to the British labor movement.

Ohio National Guard troops open fire on unarmed Vietnam War protesters at Kent State University, killing four students.

Ohio National Guard troops opened fire on unarmed students protesting the Vietnam War and the U.S. invasion of Cambodia at Kent State University, killing four students and wounding nine others. The shootings sparked nationwide student strikes and a wave of public outrage that intensified opposition to the war.

Margaret Thatcher becomes the first female Prime Minister of the United Kingdom.

Margaret Thatcher was sworn in as Britain's first female prime minister following her Conservative Party's decisive election victory, beginning an eleven-year tenure marked by privatization, confrontations with labor unions, and sweeping free-market economic reforms that fundamentally reshaped British society and politics.

Space Shuttle Atlantis launches on mission STS-30, deploying the Magellan probe toward Venus.

Space Shuttle Atlantis launched on mission STS-30, carrying the Magellan spacecraft, which it deployed toward Venus to conduct detailed radar mapping of the planet's cloud-shrouded surface. The mission produced the most comprehensive map of Venus's terrain obtained up to that point.