This dominance in South-East England, due mainly to Williams strong military, led William to (falsely) assume the rest of England was secure as well, and he returned to Normandy in 1067, placing Odo and Fitz William in charge. However, partially due to indignation at their new Norman leader and partially due to Odo and Fitz Williams harsh rule, rebellions inevitably broke out in Britain. One of Williams responses to these threats was brutal suppression, as infamously demonstrated in the harrying of the North.
Although this method was ultimately successful in suppressing the violent northern rebels as well as preventing the success of the 1069 Danish invasion, it could also be argued that through this inhumane and savage action against the Anglo-Saxons, William created more problems than he solved. He not only lost papal support but also caused further rifts between the Britons and their Norman ruler. He was widely criticised with Oderic Vitalis saying, ¦ for this act which condemned the innocent and guilty alike to die by slow starvation I cannot commend him¦ such brutal slaughter cannot remain unpunished.
Williams military is another key factor in explaining his success at controlling the Anglo-Saxons. His army not only won him victory at Hastings but was also responsible for successfully gaining control of south-east England in under two months. Its diversity (for example its combination of both naval and land forces), created a strong defence system against potential external invasions and internal rifts.
Although Swein Estrithsons summer invasion of 1069 was inevitably weakened by an apparent lack of purpose or policy, Williams military adaptability as well as the Norman savagery displayed was essentially the main factor in preventing a potential Danish success. Williamss superior army consisting of cavalry forces, infantry men, engineers and archers, not only gained him victory at Hastings but were also a contributory factor to his success at maintaining his throne.