the surviving Anglo-Danish lords or their heirs. Alan also exercised patronage in York, where he founded St Mary's Abbey in 1088. By 1086 Alan was one of the richest and most powerful men in England. In Scotland, Malcolm married the Ætheling's sister, Margaret, in 1071. Edgar sought Malcolm's assistance in his struggle against William.The marriage of Malcolm to Edgar's sister profoundly affected the history of both England and Scotland. The influence of Margaret and her sons brought about the Anglicisation of the Lowlands and provided the Scottish king with an excuse for forays into England, which he could claim were to redress the wrongs against his brother-in-law. The formal link between the royal house of Scotland and Wessex was a threat to William, who marched up to Scotland in 1072 to confront the Scottish king. The two kings negotiated the Treaty of Abernethy (1072), through which, according to the Anglo Saxon Chronicle, Malcolm became William's vassal; among the other provisions was the expulsion of Edgar Ætheling from the Scottish court. Edgar finally submitted to William in 1074. William's hold on the crown was then theoretically uncontested. In 1080 Walcher, the Bishop of Durham, was murdered by the local Northumbrians. In response, William sent his half-brother Odo, Earl of Kent north with an army to harry the Northumbrian countryside. Odo destroyed much land north of the Tees, from York to Durham, and stole valuable items from Durham monastery, including a rare sapphire-encrusted crozier. Many of the Northumbrian nobility were driven into exile. After the conquest of 1066 the Normans used the church as an agent of colonisation with most of the wealthy churches in England passing into the hands of clerics from north west France. There had been no monasteries north of Burton upon Trent in 1066 but post harrying several monasteries were built including Fountains Abbey which became one of the largest and richest. With concern that Yorkshire could be attacked or invaded by the Scots or Vikings coupled with the threat of further revolts, the Normans reorganised the defences in the area and installed men chosen for their abilities to hold on to whatever they got. They increased the number of motte-and-bailey castles they built and in 1071 work commenced above the River Swale, to build a castle at a site now known as 'Richmond'. The name 'Richmond' is derived from the Norman French meaning 'strong hill'. The Honour