1086 CE
A year in which the Almoravids crushed the Christian forces of Castile at Sagrajas, reversing Reconquista momentum in Iberia, while William the Conqueror's great Domesday survey of England was largely completed.
The Reconquista Reversed
- The Almoravid ruler Yusuf ibn Tashfin crossed from North Africa into Iberia and defeated King Alfonso VI of Castile-Leon at the Battle of Sagrajas (Zallaqa) on October 23, inflicting a devastating blow on the Christian advance in the peninsula.
- The Almoravid victory at Sagrajas temporarily halted the momentum of the Reconquista and demonstrated that the fragmented taifa kingdoms could resist Christian expansion with North African military support.
Governance & Administration
- The Domesday Book survey, ordered by William the Conqueror in 1085, was largely completed by the summer of 1086, producing an unprecedented record of English land, wealth, and population that remains one of the most remarkable administrative documents of the Middle Ages.
- William the Conqueror held a great assembly at Salisbury in August where he required all major landholders in England to swear oaths of loyalty directly to the king, reinforcing royal authority over the feudal hierarchy.
Climate & Environment
- Atmospheric carbon dioxide concentration was approximately 275 parts per million, as later confirmed by ice core analysis.
Population & Demographics
- World population is estimated to have been approximately 317 million.