| Bayeux Tapestry | A long embroidered cloth from 1070s Norman England visually depicting the Norman Conquest |
| Britannia | Roman Britain, c. 43 CE–c. 410 CE |
| Client state | A state governed under heavy influence of a more powerful state |
| Danelaw | An independent, Scandinavian-ruled territory in northern England from 886 until 954; in the intervening period, the northern territories were gradually won back by the House of Wessex |
| Ingvaeonic | The North Sea Germanic language family: Old Frisian, Old English, Old Saxon |
| Interlace | A decorative style, found in the visual arts and especially in the metalwork of early medieval northern Europe, involving intertwining ribbons, often terminating in animal heads |
| Interpretatio romana | The practice of identifying foreign deities with approximate Roman equivalents, e.g. reading Mercury for Wodan |
| Universal religion | A religion based on individual salvation |