685day.year
The Battle of Dun Nechtain is fought between a Pictish army under King Bridei III and the invading Northumbrians under King Ecgfrith, who are decisively defeated.
Pictish forces under Bridei III rout King Ecgfrith’s Northumbrian army at Dun Nechtain, preserving Pictish independence.
In 685, King Ecgfrith of Northumbria led an invasion into Pictish lands but faced a crushing defeat at Dun Nechtain. Pictish warriors commanded by King Bridei III ambushed the Northumbrians near modern-day Dunnichen in Scotland. The loss halted Northumbrian expansion and secured Pictish autonomy for generations. Ecgfrith narrowly escaped capture, while many of his nobles were killed or taken prisoner. This decisive clash reshaped the power balance in early medieval Britain.
685
Battle of Dun Nechtain
Pictish
Bridei III
Northumbrians
Ecgfrith
1217day.year
The Second Battle of Lincoln is fought near Lincoln, England, resulting in the defeat of Prince Louis of France by William Marshal, 1st Earl of Pembroke.
William Marshal leads royalist forces to victory over Prince Louis at the Second Battle of Lincoln, tipping the balance in the First Barons’ War.
During the First Barons’ War, Prince Louis of France laid siege to Lincoln Castle in 1217. William Marshal, the 1st Earl of Pembroke, arrived with loyalist troops and launched a surprise attack. Marshal’s cavalry charge broke the French-backed forces, resulting in heavy casualties and the capture of key commanders. The victory ended Louis’s campaign and strengthened King Henry III’s claim to the throne. Marshal’s reputation as a masterful commander was cemented, bringing renewed stability to England.
1217
Second Battle of Lincoln
Lincoln
Prince Louis of France
William Marshal, 1st Earl of Pembroke
1449day.year
The Battle of Alfarrobeira is fought, establishing the House of Braganza as a principal royal family of Portugal.
Supporters of King Afonso V defeat Infante Peter at Alfarrobeira, elevating the House of Braganza in Portugal.
The 1449 Battle of Alfarrobeira saw forces loyal to King Afonso V clash with those of his uncle, Infante Peter of Coimbra. The royal army achieved a decisive victory near Porto, and Peter was killed in the aftermath. The triumph solidified the House of Braganza’s status as Portugal’s foremost noble family. This outcome reshaped court dynamics and influenced royal succession for generations. The battle marked a turning point in 15th-century Portuguese politics.
1449
Battle of Alfarrobeira
House of Braganza
1520day.year
Hernan Cortés defeats Pánfilo de Narváez, sent by Spain to punish him for insubordination.
Hernán Cortés defeats Pánfilo de Narváez in 1520, eliminating the rival expedition sent to arrest him and securing his command.
In May 1520, Hernán Cortés faced an unexpected challenge when Spain sent Pánfilo de Narváez to quell his growing power.
Despite Narváez's numerical advantage, Cortés outmaneuvered him through decisive tactics and alliances with indigenous groups.
The defeat of Narváez's force removed a direct threat to Cortés's authority in Mexico.
Captured soldiers were recruited into Cortés's army, bolstering his ranks.
This triumph paved the way for his eventual conquest of the Aztec Empire.
1520
Hernan Cortés
defeats
Pánfilo de Narváez
1521day.year
Ignatius of Loyola is seriously wounded in the Battle of Pampeluna.
During the siege of Pamplona in 1521, Ignatius of Loyola was gravely injured, an event that led to his spiritual transformation and the founding of the Jesuit order.
In May 1521, as Spanish forces besieged Pamplona, a cannonball struck Spanish soldier Íñigo López de Loyola, later known as Ignatius of Loyola.
He suffered severe leg fractures and endured a prolonged, painful recovery.
During this convalescence, he immersed himself in religious texts, sparking a profound spiritual awakening.
This period of reflection led him to form a vision for a new Catholic order focused on education and missionary work.
He eventually founded the Society of Jesus (the Jesuits), which played a pivotal role in the Counter-Reformation.
The injury at Pamplona thus became the catalyst for one of the most influential religious movements in Europe.
1521
Ignatius of Loyola
Battle of Pampeluna
1631day.year
The city of Magdeburg in Germany is seized by forces of the Holy Roman Empire and most of its inhabitants massacred, in one of the bloodiest incidents of the Thirty Years' War.
During the Thirty Years’ War, Imperial forces captured Magdeburg in 1631, resulting in a catastrophic massacre of its inhabitants.
On May 20, 1631, troops of the Holy Roman Empire stormed the Protestant stronghold of Magdeburg after a prolonged siege.
The ensuing 'Sack of Magdeburg' saw widespread slaughter, with estimates of up to 20,000 civilians killed or displaced.
Entire neighborhoods were razed by fire, and the city’s infrastructure lay in ruins.
News of the atrocity horrified Europe and became symbolic of the brutal impact of religious warfare on civilian populations.
The massacre intensified propaganda campaigns, hardening attitudes on both Protestant and Catholic sides.
Magdeburg’s fall remains one of the deadliest and most notorious events of the Thirty Years’ War.
1631
Magdeburg
Holy Roman Empire
massacred
Thirty Years' War
1645day.year
Yangzhou massacre: The ten day massacre of the residents of the city of Yangzhou, part of the Transition from Ming to Qing.
In 1645, Qing forces carried out a ten-day massacre in Yangzhou amid the dynastic transition, with massive civilian casualties.
Between May 20 and 30, 1645, Qing dynasty troops under Prince Dodo besieged and captured Yangzhou in eastern China.
Following the city’s fall, soldiers were ordered to slaughter large numbers of civilians as retribution for resisting Qing rule.
Contemporary eyewitnesses record staggering death tolls, with estimates of tens of thousands of victims.
The Yangzhou massacre exemplifies the harsh measures used to suppress Ming loyalists during the Ming–Qing transition.
Reports of the atrocity spread quickly, causing fear and prompting other cities to capitulate without a fight.
This tragic event remains a poignant reminder of the human cost of regime change in Chinese history.
1645
Yangzhou massacre
Yangzhou
Transition from Ming to Qing
1741day.year
The Battle of Cartagena de Indias ends in a Spanish victory and the British begin withdrawal towards Jamaica with substantial losses.
The Battle of Cartagena de Indias concluded in 1741 with a decisive Spanish victory, forcing the British fleet to withdraw to Jamaica after heavy losses.
In May 1741, during the War of Jenkins’ Ear, Admiral Edward Vernon led a large British expedition to capture Cartagena de Indias in present-day Colombia.
Despite overwhelming naval strength, the British forces suffered from tropical diseases, supply issues, and fierce resistance by Spanish defenders under Blas de Lezo.
The conflict involved over 50 warships and thousands of soldiers but resulted in a catastrophic British defeat.
On May 20, Vernon ordered a retreat, marking one of the worst setbacks in Royal Navy history.
The Spanish victory boosted colonial morale and secured key trading ports in the Caribbean for Spain.
This battle influenced subsequent naval tactics and underscored the importance of logistics in tropical campaigns.
1741
Battle of Cartagena de Indias
Spanish
British
withdrawal
Jamaica
losses
1813day.year
Napoleon Bonaparte leads his French troops into the Battle of Bautzen in Saxony, Germany, against the combined armies of Russia and Prussia. The battle ends the next day with a French victory.
Napoleon Bonaparte leads his French troops to victory over Russian and Prussian forces at the Battle of Bautzen in Saxony.
On May 20, 1813, Emperor Napoleon Bonaparte engaged the combined Russian and Prussian armies near Bautzen in Saxony. The intense clash marked the beginning of a two-day battle in the War of the Sixth Coalition. Napoleon’s use of concentrated artillery barrages and rapid infantry maneuvers proved decisive. Despite fierce resistance, the French forces secured a strategic victory by the following day. This triumph temporarily stalled the coalition’s advance into central Europe and bolstered French morale during a critical phase of the conflict.
1813
Battle of Bautzen
Saxony
Prussia
1861day.year
American Civil War: The state of Kentucky proclaims its neutrality, which will last until September 3 when Confederate forces enter the state.
Kentucky declares neutrality in the American Civil War, attempting to keep Union and Confederate armies off its soil.
On May 20, 1861, Kentucky declared itself neutral to keep Union and Confederate armies at bay. The state legislature adopted a resolution forbidding either side from recruiting troops or using its soil for military operations. This delicate stance aimed to prevent Kentucky from becoming a battleground. However, the neutrality lasted less than three months when Confederate General Polk occupied Columbus on September 3. Kentucky’s brief neutrality highlights the divided loyalties and strategic importance of border states in the American Civil War.
1861
American Civil War
Kentucky
neutrality
September 3
Confederate
1861day.year
American Civil War: The State of North Carolina secedes from the Union.
North Carolina formally secedes from the United States, joining the Confederacy during the American Civil War.
On May 20, 1861, North Carolina became the last Deep South state to secede from the United States. The decision followed the firing on Fort Sumter and President Lincoln’s call for troops to suppress the rebellion. Voters overwhelmingly approved secession in a statewide referendum. North Carolina’s departure bolstered the Confederacy but also heightened the stakes for Union defense. This act further polarized the nation and set the stage for battles on the southern home front.
American Civil War
1864day.year
American Civil War: Battle of Ware Bottom Church: In the Virginia Bermuda Hundred campaign, 10,000 troops fight in this Confederate victory.
Union and Confederate forces clash at Ware Bottom Church in Virginia’s Bermuda Hundred campaign, resulting in a Confederate victory.
On May 20, 1864, the Battle of Ware Bottom Church unfolded as part of the Virginia Bermuda Hundred campaign. Approximately 10,000 Union and Confederate troops engaged near the eponymous church in the Chesterfield County region. The Confederate defenders, led by General Richard H. Anderson, repelled Union assaults with entrenched positions and effective artillery. The victory secured the Bermuda Hundred peninsula and delayed Union advances toward Petersburg. This clash exemplified the brutal trench warfare that would characterize the later Petersburg operations.
1864
Battle of Ware Bottom Church
Virginia
Bermuda Hundred campaign