September 21

The Kingdom of Dublin falls to Anglo-Norman invaders during their conquest of Ireland.

Anglo-Norman forces led by Richard de Clare, known as Strongbow, captured the Norse-Irish Kingdom of Dublin, a pivotal early conquest in the broader Anglo-Norman invasion of Ireland invited initially by an exiled Irish king seeking military support. The invasion established a lasting English presence and influence on the island that would shape Anglo-Irish relations for the following centuries.

The Treaty of Arras is signed, prompting Burgundy to switch its allegiance during the Hundred Years' War.

Facing military pressure and diplomatic overtures, the Duchy of Burgundy switched its allegiance from England to France under the Treaty of Arras, a significant diplomatic shift that helped tip the balance of the long Hundred Years' War in France's favor.

Jacobite troops rout British forces in under fifteen minutes at the Battle of Prestonpans.

Jacobite forces loyal to the exiled Stuart claimant to the British throne routed a government army in a shockingly brief engagement near Prestonpans, Scotland, catching the poorly prepared government troops largely by surprise in an early morning assault. The stunning early victory briefly raised Jacobite hopes of marching on London and restoring the Stuart monarchy before their eventual defeat months later.

A fire destroys much of New York City shortly after British forces occupy it during the Revolutionary War.

Shortly after British forces occupied New York City, a large fire of disputed origin swept through the city, destroying roughly a quarter of its buildings, with both sides blaming the other for what may have been an act of sabotage or simple accident amid wartime chaos.

France's National Convention formally abolishes the monarchy during the French Revolution.

France's revolutionary National Convention voted to formally abolish the monarchy, declaring France a republic for the first time in its history, a dramatic escalation of the French Revolution that set the stage for King Louis XVI's trial and execution months later.

An Anglo-French force defeats Chinese troops at the Battle of Palikao during the Second Opium War.

Combined British and French forces decisively defeated Chinese Qing dynasty troops at Palikao near Beijing during the Second Opium War, a battle notable for the doomed but courageous cavalry charges of Qing forces against superior Western firepower. The victory led directly to the occupation of Beijing and the subsequent burning of the Old Summer Palace by Anglo-French troops.

J.R.R. Tolkien's fantasy novel "The Hobbit" is first published.

J.R.R. Tolkien's beloved fantasy adventure novel, following the reluctant hobbit Bilbo Baggins on a quest with dwarves and a wizard, was published to immediate critical and commercial success, later serving as the foundation for Tolkien's more expansive "Lord of the Rings" saga.

Malta gains independence from the United Kingdom while remaining a member of the Commonwealth.

The Mediterranean island of Malta gained full independence from British colonial rule after more than a century and a half as a strategically vital British possession, while choosing to remain within the Commonwealth of Nations. Malta later became a republic in 1974, fully severing its remaining constitutional ties to the British crown while maintaining its Commonwealth membership.

Philippine President Ferdinand Marcos declares martial law, beginning years of authoritarian rule.

Citing a growing communist insurgency and civil unrest, Philippine President Ferdinand Marcos declared martial law, suspending civil liberties, shutting down independent media, and arresting political opponents. The declaration began a period of authoritarian rule that lasted over a decade and was marked by widespread human rights abuses, corruption, and the eventual accumulation of enormous personal wealth by Marcos and his family.

A powerful earthquake strikes central Taiwan, killing approximately 2,400 people.

A powerful magnitude 7.6 earthquake struck central Taiwan just after midnight, collapsing buildings and infrastructure across the densely populated region and killing approximately 2,400 people in the deadliest natural disaster to strike the island in decades. The disaster prompted significant reforms to Taiwan's building codes and earthquake preparedness and response systems in the years that followed.