On the 27th September, two days after Harold had destroyed the Viking army at Stamford Bridge, William's invasion fleet finally set sail across the Channel. Though many believe it was luck on William's part, the timing of these events seems far too good to be put down merely to the chance combination of wind and tide delaying William's invasion. The next morning they landed, unopposed, at Pevensey where a large bay provided a safe haven. The bay has long since silted up but its outline is still clear when viewed from the surrounding hills. Guarding the harbour in the 4th century had been a large Roman fort at Pevensey, the walls of which, even today, still stand almost to their original height around much of the circuit. In 1066 it stood on a small island or promontory, and William immediately refortified the site to protect this bridgehead and communications with Normandy.

The majority of the army were then transferred, on the 29th September, eastward along the coast to Hastings. Though Hastings lacked such a large harbour it had long been an important regional administrative centre. Here William constructed a castle of earth and timber, high on the cliff edge, where the ruins of a later stone castle still stand today. Hastings was an ideal base, with a territory which will have been large and wealthy enough to support a substantial army for some days. Moreover, on east and west there were large inlets from the sea encompassing an areas of some square miles. This meant that an opposing army had just one major route by which to approach the area. This was the road which led from London, through the great tracts of woodland in the Weald.

There was one very distinct pinch point, where the route from London crossed Caldbec hill and then ran along the narrow Senlac ridge. If Harold was to challenge the Norman army before it broke out from Hastings, then he was almost bound to do so here. He needed to fight on advantageous ground of his choosing, suited to the defensive infantry tactics of the English army, a location where he was able to deny the Norman cavalry their natural advantage in open, level ground.  William's choice of Hastings as his base, almost inevitably led to Harold's choice of Senlac as the battlefield where control of the kingdom would be decided.

It was not until Harold was on his way south with his retinue, returning to the capital from his victory at Stamford Bridge, that Harold received news that the Norman invasion was underway. He reached London on about the 6th October, but he did not waiting to marshal all his forces from across the country. Instead, after just a few days, he marched south from the city with those forces that were ready. It was 50 miles to the rendezvous point, at ‘the hoary apple tree’, which many believe was on Caldbec hill, less than a mile to the north of where Battle Abbey now stands. The English army arrived on the evening of the 13th October. But, unlike Harald Hardrada at Stamford Bridge, William must have been fully informed by his scouts as to the nature of the threat. Early on the morning of the 14th October he had mustered his forces and was marching the five miles north along the main road to engage the English army.