Middle Ages
Tower of London: William the Conqueror's White Tower
A great Norman stone keep that grew into a concentric royal castle and one of England's most important centres of power.
Era · c. 500 – 1500
Middle Ages
Kingdoms, crusades and plagues: the medieval world from the end of the Western Roman Empire to the fall of Constantinople.
Middle Ages
Omar Khayyam and the Jalali Calendar Reform (1079)
The Jalali calendar, a precise solar calendar beginning the year at the spring equinox, was adopted; its descendant is still used in Iran.
Middle Ages
Battle of Dyrrhachium (1081): Normans Against Byzantium
Norman victory; Alexios fled wounded, Dyrrhachium fell in February 1082 and the Normans advanced into Macedonia and Thessaly.
Middle Ages
Alexios I Komnenos: The Komnenian Restoration of Byzantium
Alexios stabilised the Byzantine Empire, recovered western Anatolia with crusader help and founded a dynasty that ruled until 1185.
Middle Ages
Mai Hume and Kanem's Conversion to Islam (c. 1085)
Kanem's ruling house became Muslim, and the Sefuwa dynasty ruled Kanem and later Bornu until 1846.
Middle Ages
Capture of Toledo (1085): Alfonso VI Takes a Great Moorish City
Toledo surrendered to Alfonso VI and became a Christian capital, prompting the Almoravid intervention in al-Andalus.
Middle Ages
Jameh Mosque of Isfahan: Seljuk Domes and the Four-Iwan Plan
The mosque became a model of Iranian mosque design, combining Seljuk domes with a four-iwan courtyard; it is a UNESCO World Heritage Site.
Middle Ages
Battle of Sagrajas (1086): Almoravids Defeat Alfonso VI
Decisive Almoravid and Andalusi victory; Alfonso VI's advance was halted, though Toledo remained in Christian hands.
Middle Ages
Domesday Book (1086): William the Conqueror's Great Survey
A detailed record of landholding and resources in most of England, still the oldest surviving public record in The National Archives.
Middle Ages
Su Song's Astronomical Clock Tower in Kaifeng (1088-1092)
A working water-powered astronomical clock about 12 metres tall, described in Su Song's illustrated treatise and later carried off by the Jurchen Jin in 1127.
Middle Ages
Shen Kuo's Dream Pool Essays (1088) and the Magnetic Compass
A wide-ranging notebook of observations that contains the earliest known clear description of the magnetic needle compass and of magnetic declination.
Middle Ages
University of Bologna (1088): The Oldest University in Europe
Bologna became the leading centre of legal studies in medieval Europe and a model for later universities, especially in southern Europe.