SCOTTISH HISTORY & HERITAGE
King Henry II took back lands in Northumbria by threat of force in 1157. Malcolm IV of Scotland had no option and this caused great upset among the Scots. After his death his brother William the Lion of Scotland wanted it back, and started the alliance with France leading to a conflict with Anglo-Norman England. He launched an invasion of England in 1174 to reclaim Northumbria. However, the Scots were heavily defeated at Alnwick and William the Lion himself, taken prisoner and sent to Normandy. He was forced to sign the Treaty of Falaise - Scotland was placed under feudal subjection to England. Northumbria was confirmed as English territory and the castles of Southern Scotland garrisoned by English troops.
Then in 1189, Richard Coeur de Lion (Richard the Lionhearted), needed money for a Crusade and agreed to give back the castles and renounce his feudal superiority over Scotland in return for 10,000 marks. Three years later, Pope Celestine III released the Scottish church from English supremacy and declared that it should be under direct jurisdiction of Rome.
It was the beginning of nearly 100 years of relative peace between England and Scotland.