I believe that Dr Crook has not found the truth about Robin Hood.
After the conquest of 1066 the Anglo-Saxon aristocracy was replaced by Norman Lords. What happened to the deposed Earls? Many fled to Scotland and other places. Some become freedom fighters such as Hereward the Wake.
Even the English Church was violated after the Conquest, when William, with the approval of the Pope, Alexander II, had many of the English-born bishops, priests and abbots ousted from their churches and monasteries and replaced by Normans. With this action of religious desecration William was able to further strengthen his control over the unfortunate English, as at that period people feared that without the sacraments of the church they would be condemned to hell and damnation. Disobey the French priests now ensconced in the English churches and you would be excommunicated and so face an eternity in hell. Friar Tuck was one of the many English monks ousted from their monasteries.
This was the period in history where Robin Hood and Friar Tuck existed and not, as later portrayed in literature, in Richard the Lion Heart’s period which was one hundred years later. In Dr Crook's narrative an even later period of history has been attributed to Robin's existence. Henry III ruled from 1216 to 1272.
Robin, an English Earl who lost his lands and title after the Conquest and Friar Tuck expelled from his monastery, both becoming “outlaws”, according to the Normans, but freedom fighters according to the English.