1338day.year

The Battle of Arnemuiden, in which a French force defeats the English, is the first naval battle of the Hundred Years' War and the first naval battle in which gunpowder artillery is used.

French forces win the first naval encounter of the Hundred Years' War at Arnemuiden, introducing gunpowder artillery at sea.
On September 23, 1338, the Battle of Arnemuiden became the first naval engagement of the Hundred Years' War. A French fleet intercepted an English merchant convoy off the coast of Arnemuiden in modern-day Netherlands. It marked the earliest recorded use of gunpowder artillery aboard ships, giving the French a crucial firepower advantage. The engagement foreshadowed a new era of maritime warfare, where cannon and firearms shaped naval tactics. Although limited in scale, Arnemuiden set the stage for protracted naval conflicts between England and France. Historians view it as a pivotal moment in the evolution of medieval naval armaments and strategy.
1338 Battle of Arnemuiden Hundred Years' War
1409day.year

The Battle of Kherlen is the second significant victory over Ming dynasty China by the Mongols since 1368.

Mongol forces achieve a significant victory over the Ming dynasty at the Battle of Kherlen.
On September 23, 1409, Mongol troops secured a decisive win against Ming China at the Battle of Kherlen. This clash in northeastern Asia was the second major Mongol triumph since their ousting from power in 1368. Leveraging superior cavalry tactics and intimate knowledge of the steppe terrain, they inflicted heavy casualties on Ming forces. The battle exposed weaknesses in Ming border defenses and prompted Beijing to strengthen fortifications. It underscored the enduring threat the Mongol khanates posed to their former empire. The victory influenced later diplomatic and military engagements between the Mongols and the Ming court.
1409 Battle of Kherlen
1459day.year

The Battle of Blore Heath, the first major battle of the English Wars of the Roses, is won by the Yorkists.

Yorkist troops win the first major battle of the Wars of the Roses at Blore Heath.
On September 23, 1459, the Battle of Blore Heath marked the opening major engagement of the English Wars of the Roses. Yorkist forces under the Earl of Salisbury ambushed a Lancastrian army near Market Drayton in Staffordshire. Despite being outnumbered, the Yorkists exploited surprise and advantageous terrain to rout the Lancastrians. The victory boosted Yorkist morale and intensified the dynastic struggle between the houses of York and Lancaster. It set a brutal precedent for the civil conflicts that would ravage England for decades. Blore Heath highlighted fractured noble loyalties and foreshadowed further bloodshed in the contest for the throne.
1459 Battle of Blore Heath
1642day.year

First English Civil War: The Battle of Powick Bridge, the first engagement between the primary field armies of the Royalists and the Parliamentarians, ended in a Royalist victory.

Royalist cavalry triumphs over Parliamentarian forces in the first combat of the English Civil War at Powick Bridge.
On September 23, 1642, the Battle of Powick Bridge marked the first military engagement of the First English Civil War. Near Worcester, a Royalist cavalry detachment clashed with and defeated a smaller Parliamentarian advance guard. Although a skirmish in scale, the fight demonstrated the effectiveness of cavalry in the conflict. The outcome boosted Royalist confidence and foreshadowed a protracted civil war across England. It influenced both sides' tactics and underscored the deep political and religious divisions within the kingdom. Historians regard Powick Bridge as the spark that ignited a broader struggle for the English throne.
1642 First English Civil War Battle of Powick Bridge Royalists Parliamentarians
1779day.year

American Revolution: John Paul Jones, naval commander of the United States, on board the USS Bonhomme Richard, wins the Battle of Flamborough Head.

John Paul Jones wins a dramatic naval victory aboard the USS Bonhomme Richard at Flamborough Head.
On September 23, 1779, during the American Revolutionary War, naval captain John Paul Jones engaged HMS Serapis off the coast of England at the Battle of Flamborough Head. Despite commanding the battered USS Bonhomme Richard, Jones famously declared, "I have not yet begun to fight!" His crew boarded the British vessel in intense close-quarters combat, ultimately forcing its surrender after hours of fierce action. The victory provided a vital morale boost to the revolutionary cause and showcased American naval determination. It also secured greater support from France and cemented Jones's reputation as a bold maritime commander. The battle remains one of the most celebrated naval engagements of the Revolution.
1779 American Revolution John Paul Jones USS Bonhomme Richard Battle of Flamborough Head
1803day.year

Second Anglo-Maratha War: The Battle of Assaye is fought between the British East India Company and the Maratha Empire in India.

British East India Company forces under Arthur Wellesley defeat the Maratha Empire at the Battle of Assaye.
On September 23, 1803, the Battle of Assaye saw British East India Company troops clash with the Maratha Empire in western India. Led by Major General Arthur Wellesley, later the Duke of Wellington, the British executed a bold dawn assault across the Kaitna River. Despite facing a numerically superior enemy, Wellesley’s forces captured key Maratha artillery positions and routed their army. The victory significantly strengthened British influence on the subcontinent and boosted Wellesley’s military reputation. Assaye is often cited as one of Wellesley’s finest battles for its daring tactics and decisive outcome. The engagement shifted the regional balance of power and paved the way for further British expansion in India.
1803 Second Anglo-Maratha War Battle of Assaye British East India Company Maratha Empire
1821day.year

Tripolitsa, Greece, is captured by Greek rebels during the Greek War of Independence.

Greek revolutionaries capture Tripolitsa, delivering a major blow to Ottoman control.
On September 23, 1821, insurgent forces of the Greek War of Independence seized the fortified city of Tripolitsa from Ottoman rule. The fall of Tripolitsa in the Peloponnese region effectively broke the Ottoman stronghold in southern Greece. Following the victory, Greek fighters executed many Ottoman officials and settlers, consolidating revolutionary control. News of the triumph galvanized European public opinion and increased support for the Greek cause. The capture marked a turning point in the struggle for independence and the eventual establishment of a Greek state. Historians view Tripolitsa’s fall as a decisive moment that legitimized and energized the movement for nationhood.
1821 Tripolitsa
1868day.year

The Grito de Lares occurs in Puerto Rico against Spanish rule.

The Grito de Lares was the first major uprising in Puerto Rico against Spanish colonial rule in 1868.
On September 23, 1868, Puerto Rican rebels launched the Grito de Lares, an armed revolt against Spanish authority. Led by Ramón Emeterio Betances and Segundo Ruiz Belvis, insurgents sought independence for the island. Although the rebellion was quickly suppressed by Spanish forces, it became a symbol of Puerto Rican nationalism. The event inspired future movements for autonomy and cultural identity in Puerto Rico. Today, the Grito de Lares is commemorated as a key moment in the island's quest for self-determination.
1868 Grito de Lares
1899day.year

The American Asiatic Squadron destroys a Filipino battery at the Battle of Olongapo.

During the Philippine–American War, the US Asiatic Squadron attacked a Filipino artillery battery at Olongapo in 1899.
On September 23, 1899, the American Asiatic Squadron under Commodore George Dewey engaged Filipino forces defending Olongapo. The naval squadron bombarded and destroyed an artillery battery guarding the entrance to Subic Bay. This victory secured a strategic harbor for the US Navy and disrupted Filipino coastal defenses. The Battle of Olongapo exemplified the naval aspect of the broader Philippine–American War. It highlighted the importance of maritime power in the conflict for control over the archipelago.
1899 Battle of Olongapo
1913day.year

The United Mine Workers of America launch a strike which eventually escalated into the Colorado Coalfield War.

The United Mine Workers strike of 1913 ignited the Colorado Coalfield War, a bitter labor conflict.
On September 23, 1913, the United Mine Workers of America launched a strike across Colorado coal mines. Miners protested low wages, unsafe conditions, and company dominance over local towns. The strike escalated into the Colorado Coalfield War, marked by violent clashes between strikers and mine guards. Key incidents included the Ludlow Massacre in April 1914, where dozens of miners and their families were killed. The conflict drew national attention to labor rights and led to reforms in mining labor practices.
1913 United Mine Workers of America Colorado Coalfield War
1918day.year

World War I: The Battle of Haifa takes place in present-day Israel, part of the Ottoman Empire at that time.

The Battle of Haifa in World War I saw Allied forces capture the strategic city from the Ottoman Empire.
On September 23, 1918, British-led forces, including Indian Army units, launched an assault on Haifa in Palestine. The well-defended port city was a vital link for Ottoman supply lines in the region. After intense fighting, the Allies seized Haifa, securing control of the surrounding coastal region. The victory opened the way for further advances into Ottoman-held Syria and Lebanon. The battle demonstrated the importance of coordinated infantry and cavalry tactics in desert warfare.
1918 World War I The Battle of Haifa Israel Ottoman Empire
1942day.year

World War II: The Matanikau action on Guadalcanal begins: U.S. Marines attack Japanese units along the Matanikau River.

The Matanikau action marks a significant engagement on Guadalcanal during WWII, where U.S. Marines attacked Japanese positions along the Matanikau River.
On September 23, 1942, U.S. Marines commenced the Matanikau action against entrenched Japanese forces on Guadalcanal. The operation aimed to secure Henderson Field and disrupt enemy supply lines by seizing strategic river crossings. Marines moved through dense jungle terrain under heavy fire, engaging in fierce close-quarters combat. Despite stiff resistance and challenging conditions, American forces pressed deep into Japanese defenses. The battle demonstrated the determination and adaptability of U.S. troops in the Pacific theater. This engagement set the stage for subsequent operations that would eventually secure the island and shift momentum in the Allies’ favor.
1942 World War II Matanikau action Guadalcanal Matanikau River