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A century

9th century

7 stories from this century.

The Cabinet June 27, 2026 · Baghdad

The 9th-Century Baghdad Mathematician Whose Name Became the Word 'Algorithm' and Whose Book Title Became 'Algebra'

Muhammad ibn Musa al-Khwarizmi worked at the House of Wisdom in Baghdad under Caliph al-Ma'mun in the 820s. His *al-Kitāb al-mukhtaṣar fī ḥisāb al-jabr wa-l-muqābala* gave Europe the word algebra. The Latinised version of his name — algoritmi — gave Europe the word algorithm. He introduced the Hindu decimal numeral system to the Arabic-speaking world and from there to Europe.

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The Cabinet June 27, 2026 · Old Saint Peter's Basilica, Rome

The Christmas Day Coronation in 800 CE at Which Pope Leo III Crowned the Frankish King Charlemagne Emperor of the Romans in Saint Peter's Basilica

Pope Leo III placed an imperial crown on Charlemagne's head during Christmas Day mass in Old Saint Peter's Basilica on 25 December 800 CE. The Roman congregation acclaimed Charlemagne as emperor. The act revived a Western Roman imperial title that had been vacant since 476 CE. The political relationship between the Catholic papacy and the European emperors that followed substantially structured the next thousand years of European politics.

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The Footnote June 26, 2026 · Caithness, northern Scotland

The Viking Earl Killed by a Severed Head Tied to His Saddle

Sigurd Eysteinsson — known as Sigurd the Mighty, the second Norse Earl of Orkney — defeated the Scottish chieftain Máel Brigte in 892 AD, beheaded him, and tied the head to his saddle as a trophy. The dead man's tooth scratched Sigurd's calf during the ride home. The wound became infected. Sigurd died of sepsis approximately three weeks later.

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The Footnote June 25, 2026 · Corvey Abbey, Westphalia

The Saxon Abbey That Housed the Relics That Drew the Dancing Pilgrims From Aachen and Strasbourg

Saint Vitus was a 4th-century Sicilian Christian martyr whose relics were translated to the Saxon abbey of Corvey on the upper Weser in 836 AD. The Corvey shrine became the principal medieval European pilgrimage site for sufferers of involuntary collective dancing afflictions — including the Aachen mania of 1374 and the Strasbourg plague of 1518.

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The Cabinet June 24, 2026 · Borobudur, Central Java

The Largest Buddhist Monument in the World Had Been Buried for a Thousand Years When Stamford Raffles Asked About It

Borobudur is a 9th-century Mahayana Buddhist monument on the central plain of Java — 2,672 relief panels, 504 buddha statues, six concentric square terraces topped by three circular ones. It had been abandoned by about 1100 AD and buried under volcanic ash and jungle vegetation for the next seven centuries. [Stamford Raffles](/articles/stamford-raffles-singapore) heard about it in 1814 and sent a survey team.

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The Cabinet June 24, 2026 · Borobudur, Central Java

The Largest Buddhist Monument in the World Was Buried for a Millennium and Rediscovered by Stamford Raffles

Borobudur is a 9th-century Mahayana Buddhist temple complex in central Java with about 2,672 narrative relief panels and 504 Buddha statues. It was abandoned in the 14th century, progressively buried by jungle and volcanic ash, and rediscovered in 1814 on orders of the British lieutenant-governor Sir Stamford Raffles.

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