William I wanted to punish the north for 3 rebellions and Robert Cumin's murder
The failed rebellions had led to guerrilla warfare against Norman soldiers, the rebels were hard to find and fight
William wanted to ensure the northern Danelaw could not support Sweyn if he returned
Homes, food, seed, land and livestock were destroyed
Over 100,000 died, many from starvation and some cannibalism
Villages from York to Durham were left uninhabited
The North did not rebel again