An introduction to the Norman Conquest, an event which would link the English kingdom with Europe, especially France, for 500 years.
It completely changed the nation's aristocracy, church and administration, bringing in a new language and cultural influences.
This was reflected in art and architecture too, especially military architecture and the castle.
The Conquest has since been of enduring political significance: in the 17th century radicals spoke of the "Norman Yoke" on traditional English liberties, while 19th-century scholars debated whether it was "good" or "bad" for the nation's development.
Today, the Conquest is still a hotly-debated issue, popularly regarded as the last time England was successfully invaded.