The duke then continued his march to Dover, where there was a large body of
people collected, because they thought the position impregnable, the castle
standing on the summit of a steep rock, overhanging the sea. The garrison, however,
struck with panic at the duke's approach, were preparing to surrender, when
some Norman squires, greedy for spoil, set the place on fire, and the devouring
flames spreading around, many party were ruined and burnt. The duke, compassionating
those who were willing to render him their submission, ordered them to be paid
the cost of rebuilding their houses, and their other losses. The castle being
taken, eight days were spent in strengthening the fortifications.--Orderic Vitalis