193day.year
The distinguished soldier Septimius Severus is proclaimed emperor by the army in Illyricum.
In 193 AD, Septimius Severus was proclaimed emperor by his troops in Illyricum, marking a decisive moment in Roman history.
Septimius Severus rose through the Roman military ranks to become one of the most influential emperors of the Late Roman Empire. On April 9, 193 AD, his legions in Illyricum proclaimed him emperor amid civil unrest following the assassination of Pertinax. This acclamation was a pivotal step in the Year of the Five Emperors, a period of fierce competition for the throne. Severus leveraged the support of his African and Illyrian soldiers to march on Rome, rapidly outmaneuvering rival claimants. His ascent heralded reforms to the military and administrative structures that would shape the empire for decades.
193
Septimius Severus
Illyricum
475day.year
Byzantine Emperor Basiliscus issues a circular letter (Enkyklikon) to the bishops of his empire, supporting the Monophysite christological position.
In 475 AD, Emperor Basiliscus issued the Enkyklikon to support Monophysite doctrine, challenging established Church teachings in the Byzantine Empire.
In 475 AD, Emperor Basiliscus circulated a letter known as the Enkyklikon to the bishops of the Byzantine Empire endorsing Monophysite Christology, which held that Christ had a single divine nature. This move aimed to solidify support among eastern provinces but undermined the Chalcedonian consensus established in 451. The decree sparked theological controversy and political turbulence, as many bishops refused to accept the imperial edict. The religious schism weakened Basiliscus’s authority and contributed to his eventual overthrow by Emperor Zeno. His attempt to enforce doctrine by imperial decree illustrates the intricate ties between theology and governance in the late Roman world.
475
Byzantine Emperor
Basiliscus
Monophysite
christological
537day.year
Siege of Rome: The Byzantine general Belisarius receives his promised reinforcements, 1,600 cavalry, mostly of Hunnic or Slavic origin and expert bowmen. Despite shortages, he starts raids against the Gothic camps and Vitiges but is forced into a stalemate.
During the Gothic War, Belisarius received fresh Hunnic and Slavic cavalry reinforcements at the Siege of Rome in 537 AD, yet the stalemate with the Goths persisted.
In 537 AD, Belisarius led Byzantine forces in defending Rome against the Ostrogothic siege during Justinian’s Gothic War. On April 9, he finally received the 1,600-strong cavalry contingent, composed largely of skilled Hunnic and Slavic archers. Bolstered by these reinforcements, Belisarius conducted daring raids on enemy encampments and challenged the Gothic king Vitiges. Despite his tactical ingenuity, shortages of supplies and manpower prevented a decisive victory, resulting in a protracted stalemate. The siege exemplified the complex interplay of diplomacy, strategy, and multicultural forces in Justinian’s campaign to reconquer the Western Empire.
537
Siege of Rome
Belisarius
Hunnic
Slavic
bowmen
Gothic
Vitiges
1241day.year
Battle of Liegnitz: Mongol forces defeat the Polish and German armies.
In 1241, Mongol forces inflicted a crushing defeat on a Polish-German coalition at the Battle of Liegnitz, showcasing their superior tactics in Europe.
In April 1241, a Mongol army under General Subutai engaged a coalition of Polish knights and German forces near Liegnitz (present-day Legnica, Poland). The European knights were taken by surprise by the Mongols’ feigned retreats and devastating light cavalry tactics. Despite fierce resistance, the heavy cavalry charges of the crusader knights could not withstand the mobile Mongol archers and coordinated assaults. The crushing victory opened Central Europe to further Mongol incursions and instilled widespread fear among the region’s rulers. Although the Mongols withdrew soon after due to internal succession issues, the battle demonstrated the effectiveness of steppe warfare against medieval armies.
1241
Battle of Liegnitz
Mongol
1288day.year
Mongol invasions of Vietnam: Yuan forces are defeated by Trần forces in the Battle of Bach Dang in present-day northern Vietnam.
During the Mongol invasions of Vietnam in 1288, Trần dynasty forces achieved a decisive naval victory at the Battle of Bach Dang River.
In March–April 1288, the Yuan dynasty fleet attempted to invade Đại Việt via the Bach Dang river under Kublai Khan’s mandate. Trần Hưng Đạo, the Vietnamese commander, ordered steel-tipped wooden stakes planted in the riverbed and timed a counterattack with the ebbing tide. As the Yuan ships grew trapped, Vietnamese warships launched volleys of fire arrows and close combat assaults. The destruction of the Mongol fleet forced Kublai Khan to end his third invasion and solidified the Trần dynasty’s sovereignty. This battle remains celebrated in Vietnam for its ingenious use of terrain and popular resistance against a dominant empire.
1288
Mongol invasions of Vietnam
Yuan
Trần
Battle of Bach Dang
1388day.year
Despite being outnumbered 16:1, forces of the Old Swiss Confederacy are victorious over the Archduchy of Austria in the Battle of Näfels.
On April 9, 1388, the Old Swiss Confederacy secured a surprising victory against the Archduchy of Austria at the Battle of Näfels.
In the spring of 1388, Austrian forces launched an offensive to subjugate the cantons of Glarus, a member of the Old Swiss Confederacy. At Näfels in eastern Switzerland, the Swiss defenders, though outnumbered sixteen to one, used their knowledge of the mountainous terrain to set ambushes and defensive positions. Under the leadership of local commanders, they repelled multiple cavalry charges and exploited narrow passes to neutralize enemy advantages. The stunning Swiss victory not only lifted the siege of Glarus but also led to the Peace Treaty of Vienna in 1389, affirming the confederation’s independence. Näfels became a symbol of Swiss courage and solidarity in the face of overwhelming odds.
1388
Old Swiss Confederacy
Archduchy of Austria
Battle of Näfels
1454day.year
The Treaty of Lodi is signed, establishing a balance of power among northern Italian city-states for almost 50 years.
In 1454, Italian rulers signed the Treaty of Lodi to create a 50-year balance of power and peace among the major city-states.
On April 9, 1454, representatives of Milan, Naples, and Florence concluded the Treaty of Lodi, ending decades of internecine warfare among northern Italian states. The agreement created a diplomatic framework and mutual defense pacts to maintain equilibrium among Milan, Venice, Florence, Naples, and the Papal States. This balance of power fostered over five decades of stability, enabling the flourishing of art, commerce, and humanist culture during the High Renaissance. The treaty’s success inspired early modern principles of collective security and diplomatic congresses. Although the peace eventually collapsed in the late 15th century, the Lodi alliance remains a landmark in the history of European statecraft.
1454
Treaty of Lodi
1511day.year
Resettled Shiite Muslims rise up in the Şahkulu rebellion under the leadership of Şahkulu against the Ottoman Empire.
In 1511, Shiite Muslims in Anatolia rebelled under Şahkulu’s leadership, challenging the Sunni authority of the Ottoman Empire.
In April 1511, discontented Shiite communities in Anatolia rallied under the leadership of Şahkulu, a Turkmen agitator claiming divine support. The rebels targeted Ottoman tax collectors and symbols of Sunni authority, seizing several towns and drawing followers from disenfranchised Turkmen tribes. Sultan Bayezid II responded by dispatching a large army to confront the insurgency, culminating in the rebels’ defeat at the hands of experienced Janissary forces. Although Şahkulu himself was killed in battle, the uprising exposed underlying sectarian tensions that would later influence the Safavid–Ottoman rivalry. The rebellion foreshadowed the role of religious identity in shaping early 16th-century Ottoman politics.
1511
Şahkulu rebellion
Şahkulu
Ottoman Empire
1609day.year
Eighty Years' War: Spain and the Dutch Republic sign the Treaty of Antwerp to initiate twelve years of truce.
In 1609, Spain and the Dutch Republic signed the Twelve Years’ Truce with the Treaty of Antwerp, pausing hostilities during the Eighty Years’ War.
By April 1609, three decades of brutal conflict between Habsburg Spain and the Dutch Republic had ravaged the Low Countries. Negotiators convened in Antwerp to broker a temporary truce, culminating in the Twelve Years’ Truce signed on April 9, 1609. The agreement recognized de facto independence for the Dutch, allowing for normalized trade and the exchange of prisoners. This pause in hostilities fostered economic recovery and allowed the Dutch Golden Age to flourish in the early 17th century. Though hostilities resumed in 1621, the truce shaped the political landscape of Northwest Europe for generations.
1609
Eighty Years' War
Spain
Dutch Republic
Treaty of Antwerp
1609day.year
Philip III of Spain issues the decree of the "Expulsion of the Moriscos".
On April 9, 1609, King Philip III of Spain decreed the expulsion of the Moriscos, redefining Spain’s religious and social fabric.
Philip III of Spain, influenced by religious and political advisors, signed the royal decree expelling Moriscos on April 9, 1609, aiming to eliminate residual Islamic influence. Over the following years, an estimated 300,000 former Muslims were forced to leave Spain, many suffering hardship during voyages and resettlement. The expulsion led to significant loss of agricultural expertise, especially in regions like Valencia, and disrupted local economies. While framed as a measure to ensure religious unity and state security, it underscored the intolerance and absolutism of the Habsburg monarchy. Historians view the Moriscos’ fate as a poignant example of early modern forced migration and its enduring cultural legacies.
Philip III of Spain
the decree of the "Expulsion of the Moriscos"
1682day.year
Robert Cavelier de La Salle discovers the mouth of the Mississippi River, claims it for France and names it Louisiana.
French explorer Robert Cavelier de La Salle becomes the first European to reach the mouth of the Mississippi River and claims the territory for France, naming it Louisiana.
In 1682, French explorer Robert Cavelier de La Salle completed a bold expedition across North America to the Gulf of Mexico. He navigated the full length of the Mississippi River and reached its mouth on April 9. Claiming the vast region for King Louis XIV, he named it Louisiana in honor of the monarch. This act laid the foundations for French colonial influence in the interior of the continent. La Salle's claim would shape future geopolitical rivalries between European powers. His expedition opened new routes for trade and exploration, setting the stage for the fur trade. Although subsequent French efforts to colonize the area faced challenges, his naming of Louisiana remains a key moment in North American colonial history.
1682
Robert Cavelier de La Salle
Mississippi River
Louisiana
1784day.year
The Treaty of Paris, ratified by the United States Congress on January 14, 1784, is ratified by King George III of the Kingdom of Great Britain, ending the American Revolutionary War. Copies of the ratified documents are exchanged on May 12, 1784.
The 1784 Treaty of Paris is formally ratified by King George III, officially ending the American Revolutionary War.
On April 9, 1784, King George III ratified the Treaty of Paris, which Congress had approved on January 14. This formal ratification ended the years-long struggle between Great Britain and its Thirteen Colonies in North America. Under the treaty, Britain recognized the independence of the United States and established boundaries for the new nation. Copies of the ratified documents were exchanged later that year on May 12. The agreement set a precedent for diplomatic resolution of conflict and reshaped the balance of power in the Atlantic world. It also paved the way for American westward expansion and international trade. The treaty stands as a landmark in both American and British history.
1784
Treaty of Paris
United States Congress
King George III
Kingdom of Great Britain
American Revolutionary War