Browse Historical Events by Month:
Battles, revolts, and explorations. Learn about the noteworthy events in May that have taken place throughout the ages. Dates for earlier events may be approximate.
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Persian mathematician, astronomer, and poet, Omar Khayyam, was born on May 18, 1048, in Nishapur, Khorasan (modern-day Iran). A giant of the Islamic Golden Age, he is renowned for developing the Jalali calendar, which was more precise than the Gregorian calendar, geometric solutions to cubic equations and writing the famous quatrains poems. (Rubaiyat)
Alfonso VI of Castile captures the city of Toledo, Spain, from the Moorish Taifa kingdom on May 24, 1085, after a lengthy siege. The fall of Toledo, after over 370 years of Muslim control was a crucial moment in the Christian reconquest of the Iberian Peninsula, The city went on to become the capital of the united kingdom of Castilla y León.
The Reconquista of Spain took nearly 800 years from the early 8th century Umayyad invasion in 711 or the Battle of Covadonga until 1492, when the last Muslim stronghold, the Emirate of Granada, fell to the Catholic Monarchs of Spain, Making it one of history's longest conflicts.
The First Crusade forces led by Raymond of Toulouse, failed to capture the fortress of Arqa (in todays Lebanon) from the Fatimids. The siege began in February but failed to breach the defenses and was abandoned on May 13, 1099. The First Crusade army continued south and captured Jerusalem on July 15, 1099.
King Baldwin I of Jerusalem, captures the port city of Acre from the Fatimids on May 25, 1104 with support from a Genoese fleet after a 20-day siege, solidifying control over he Kingdom of Jerusalem.
The victory came after failed attempts in 1103. After the victory, Baldwin went on to capture, other coastal cities like Beirut in 1110 and Sidon in 1111.
Baldwin I, was the youngest son of Eustace II, Count of Boulogne,(present day France) and Ida of Lorraine. the first count of Edessa ( ancient center of early Christianity in Upper Mesopotamia known today as Şanlıurfa in southeastern Turkey). Baldwin joined the crusader army of his brother Godfrey of Bouillon and became one of the most successful commanders of the First Crusade. He was king of Jerusalem from 1100 until his death in 1118.
Henry V, Holy Roman Emperor and King of Germany, dies in Utrecht on May 23, 1125 without an heir, marking the end of the Salian dynasty. He was succeeded by Lothair of Supplinburg, Duke of Saxony.
He was the son of Henry IV and married Matilda, daughter of Henry I of England, but left no direct heirs. Henry V is known for settling the Investiture Controversy with the Concordat of Worms in 1122.
Alfonso VII of Spain is crowned Emperor of Spain at the Cathedral of Leon on May 26, 1135. When he died in 1157, the Kingdom of Leon was inherited by his son Fernando II of León and the Kingdom of Castille was inherited by his oldest son Sancho III de Castilla.
Alfonso VII became the King of Galicia, Leon, and Castile on March 10, 1126. following the death of his mother, Queen Urraca, He began to consolidate power over the territories which had been under the influence of his stepfather, Alfonso I of Aragon. Prior to that, Alphonso VII had been crowned and anointed King of Galicia when he was a six year old child in 1111 at the cathedral of Santiago de Compostela .The ceremony was orchestrated by Diego Gelmírez, the Bishop of Compostela, and the Count of Traba to secure his position against his mother, Queen Urraca, who ruled the united throne of León-Castile-Galicia.
The Second Crusade starts as European forces begin their journey on c. May 15, 1147.
Eleanor of Aquitaine marries Henry Plantagenet, on May 18, 1152. Henry later becomes King Henry II of England.
Henry Plantagenet, (later King Henry II of England) marries Eleanor of Aquitaine on May 18, 1152 in Poitiers, France, just weeks after her marriage annulment from Louis VII of France.
The strategic union formed the Angevin Empire combining Henry’s territories in Normandy and Anjou with Eleanor’s vast inheritance of Aquitaine, also creating a powerful but often turbulent .alliance.
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Malcolm IV became King of Scotland at age 12 on May 27, 1153, following the death of his grandfather, David I, on May 24, 1153. His short reign was marked by challenges due to his youth, He died in 1165 at age 24.
The Battle of Monte Porzio is fought on May 29, 1167, resulting in a significant victory for Holy Roman Emperor Frederick I Barbarossa against the Commune of Rome, who supported Pope Alexander III.
Pope Alexander III was forced to flee to Benevento. Frederick Barbarossa went and entered Rome, where he installed an antipope, Paschal III. Barbarossa's success short lived when a sudden outbreak of plague devastated his army, forcing him to retreat to Germany.
The Battle of Legnano is fought in Lombardy, Italy, on May 29, 1176, resulting in the Lombard League defeating the forces of Emperor Frederick I Barbarossa, in a significant setback for imperial power stopping Frederick's effort to reassert control over the region shifting the region towards Italian independence and forcing the Empire to negotiate.
Pope Alexander III issues a papal bull recognizing Portugal as an independent kingdom. While Afonso Henriques had been using the title of king since 1139 and Portugal's independence had been recognized by León in the 1143 Treaty of Zamora, the papal bull was vital in medieval Europe, for a new kingdom to be fully accepted as a sovereign entity. The bull also gave papal blessing to Portugal's conquests of land from the Moors during the Reconquista.
Holy Roman Emperor Frederick I Barbarossa and 100,000 crusaders depart Regensburg for the Third Crusade on May 11, 1189. Called the Kings's Crusade, led by three European monarchs of Western Christianity (Philip II of France, Richard I of England and Frederick I, Holy Roman Emperor); it attempted to reconquer the Holy Land following the capture of Jerusalem by the Ayyubid sultan Saladin in 1187.
The Crusade did not achieve its primary goal to recapture Jerusalem from Saladin, but it successfully regained vital coastal territory, including Jaffa and Acre and Jaffa and it established a stable, Crusader presence that lasted for another century
John, also called John Lackland, becomes King of England after the death of his brother Richard II (The Lionheart). King John's coronation took place on May 27, 1199 at Westminster Abbey. He was King of England until his death in 1216.
King Philip II of France and King John of England sign the Treaty of Le Goulet, on May 22, 1200 ending a succession conflict between John and his nephew Arthur of Brittany after Richard I's death.
Under the treaty, Philip recognized John as king in exchange for 20,000 marks, acknowledgment of Philip's overlordship over John's French lands, and the cession of Évreux and the Norman Vexin to France. The peace was temporary, as Philip would resume hostilities in 1202, leading to England's loss of continental Normandy by 1204.
Baldwin I of Flanders is crowned the first Latin Emperor of Constantinople during the Fourth Crusade.
King John surrenders the kingdom of England and Ireland to Pope Innocent III, on May 15, 1213 and receives them back as a papal fief; ending the Papal interdict and becoming a vassal of the Pope.
The action allowed John to resolved a six year dispute over the appointment of Stephen Langton as Archbishop of Canterbury, which had led to an interdict on England and John's own excommunication and gained a powerful ally against a planned French invasion by Philip II. As a condition of the fiefdom, John agreed to pay an annual tribute of 1,000 marks (700 for England and 300 for Ireland).England remained a nominal papal fief for over 150 years. The status was finally rejected in 1365 when the English Parliament declared John's original surrender invalid because it lacked the consent of the bishops and barons.
The Second Battle of Lincoln takes place on May 20, 1217, during the First Barons' War in England. It was a decisive conflict, fought at Lincoln Castle in England.
King Louis IX of France begins to rule independently at age 20 on May 27, 1234. He also married Margaret of Provence on the same date. He had been crowned at age 12 in 1226 and had been under his mother Blanche of Castile's regency since then. Blanche continued to be a trusted counsel until her death in 1252.
