Century

11th Century

5 sourced events from this period.

Events

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1054

Science 11th Century East Asiahigh

Chinese Astronomers Record Bright Supernova in Taurus

In the Song Dynasty capital of Kaifeng, court astronomers maintained detailed celestial logs of temporary 'guest stars.' On the morning of July 4, 1054, they noted a brilliant new object several degrees southeast of Zeta Tauri in the constellation Taurus. The star shone brightly enough to be visible in daylight for 23 days, rivaling Venus in intensity and appearing yellow at first. Contemporary records in the Sung-shih describe its gradual fading over the following months until it disappeared from view in April 1056 after roughly 653 days of naked-eye visibility. Modern astronomy identifies this event as the supernova SN 1054, whose remnant is the Crab Nebula, a pulsar-powered cloud of gas expanding at thousands of kilometers per second. The precise Chinese documentation provided one of the earliest reliable records of a galactic supernova visible from Earth.

Why it matters: The observation supplied critical data for understanding stellar evolution and the life cycles of massive stars. It enabled later identification of the Crab Nebula as the first confirmed supernova remnant and supported studies of pulsars and high-energy astrophysics. Chinese records remain foundational references in supernova catalogs used by observatories worldwide.

Event Detail Daily Earth View

1054

Culture 11th Century Europehigh

Great Schism Begins in Constantinople

By the mid-eleventh century, longstanding tensions divided the Christian church over issues of papal authority, the filioque clause in the Nicene Creed, and liturgical practices. In 1054, Pope Leo IX sent Cardinal Humbert of Silva Candida as legate to Constantinople to address disputes with Patriarch Michael I Cerularius. On July 16, during a Saturday liturgy in Hagia Sophia, Humbert placed a bull of excommunication against the patriarch and his followers on the altar. Cerularius responded in kind, excommunicating the papal legates. Historians view this exchange as the symbolic start of the East-West Schism separating Roman Catholicism and Eastern Orthodoxy. The event crystallized centuries of cultural, political, and theological divergence between the Latin West and Greek East.

Why it matters: The schism permanently divided Christianity into Western and Eastern branches, shaping European politics, crusades, and church-state relations for the next millennium. It influenced the fall of Constantinople in 1453 and ongoing ecumenical efforts today. The divide affected alliances during the Ottoman expansion and Reformation-era conflicts.

Event Detail

1071

Military 11th Century Middle East & North Africahigh

Seljuq Turks Defeat Byzantines at Manzikert

The Byzantine Empire in the 11th century faced mounting pressure from expanding Seljuq Turk forces in Anatolia and Armenia. Emperor Romanos IV Diogenes sought to counter this threat by leading a large army eastward. On August 26, 1071, near the town of Manzikert, the Byzantine forces engaged the army of Sultan Alp Arslan. Despite initial advantages, poor coordination, desertions, and effective Seljuq tactics led to a decisive defeat. Romanos IV was captured, and much of the Byzantine army was destroyed or scattered. The immediate result opened Anatolia to further Turkic incursions and weakened central Byzantine authority.

Why it matters: The defeat accelerated the loss of Byzantine control over Anatolia, facilitating the gradual Turkification of the region and contributing to the empire's long-term decline. It also influenced later events, including appeals to the West that helped precipitate the First Crusade.

Event Detail US Military Atlas

1099

Military 11th Century Middle East & North Africahigh

Crusaders Capture Jerusalem During First Crusade

By the late 11th century, Seljuk Turkish control over Jerusalem had intensified persecution of Christians, prompting Byzantine Emperor Alexius I to seek Western aid. Pope Urban II responded in 1095 with a call for crusade to recover the Holy Land. A force of roughly 4,000 knights and 25,000 infantry, led by figures including Godfrey of Bouillon and Bohemond of Taranto, advanced eastward, capturing Nicaea and Antioch after prolonged sieges. Reduced to about 1,200 cavalry and 12,000 infantry by mid-1099, the crusaders reached Jerusalem on June 7 and constructed massive siege towers. On July 15, Godfrey’s troops breached the walls at the Gate of Saint Stephen, allowing the full army to enter and seize the city after weeks of fighting.

Why it matters: The capture established Christian control over Jerusalem and enabled the creation of four Crusader states in the Levant, reshaping Levantine politics for nearly two centuries. It also intensified Christian-Muslim conflict in the region and inspired subsequent crusades while embedding the event in European religious and military memory.

Event Detail US Military Atlas

1099

Military 11th Century Middle East & North Africahigh

Crusaders Defeat Fatimids at Battle of Ascalon

Following the capture of Jerusalem in July 1099 during the First Crusade, Crusader forces under leaders including Godfrey of Bouillon faced a large Fatimid army advancing from Egypt near the coastal fortress of Ascalon. The Crusaders, numbering around 1,200 knights and several thousand infantry, formed a defensive square and launched a surprise attack on the larger Muslim force. On August 12, the battle unfolded with intense fighting that saw the Fatimids routed, their camp captured, and thousands killed or dispersed. This engagement marked the final major action of the First Crusade, securing the Crusader foothold in the Levant for the immediate future. The victory prevented an early counteroffensive against the newly established Kingdom of Jerusalem.

Why it matters: The Battle of Ascalon consolidated Crusader control over Jerusalem and surrounding territories, enabling the establishment of Crusader states that endured for nearly two centuries. It demonstrated effective combined arms tactics by European knights against numerically superior forces and influenced subsequent Crusades and Mediterranean power dynamics.

Event Detail US Military Atlas