In these words are revealed the convictions that dominated Cromwell's action at this period of his life. So far as it lay in him, he would never admit that Scotland, still less that Ireland, should impose a government upon England. On July 12 he set out for Ireland. Before he could embark he received the welcome news that Michael Jones had defeated Ormond at Rathmines, and that Dublin was consequently out of danger. When he landed at Dublin, his intention was, as soon as possible, to make his way into Munster and rally round him the Protestant colonists who formed a considerable part of the population of the towns on the coast. It was, however, necessary first to protect Dublin from an attack from the north, from which quarter Owen O'Neill, who, after long hesitation, had thrown in his lot with Ormond, was expected to advance. Accordingly, on September 1, Cromwell marched upon Drogheda, which was held for the King by a garrison of about 2,800 men, mainly composed of Irishmen, under Sir Arthur Aston. On the 10th Cromwell summoned the place, and on the refusal of the governor to surrender opened a cannonade on the south-eastern angle. It was impossible for the garrison--short of ammunition as it was--to hold out long, and on the second day, when a breach had been effected, Cromwell gave the word to storm. The assailants, though twice driven back, were, on the third attempt, successful. Aston, with about three hundred men, took refuge on a huge artificial mound, known as the Mill Mount. Angry at the prolonged resistance, Cromwell gave the word to put to the sword all who were in arms. The hasty word was ruthlessly obeyed, and some two thousand men were slaughtered in cold blood. There is no doubt that in what he did, Cromwell was covered by the strict law of war, which placed a garrison refusing surrender outside the pale of mercy; but the law had seldom been acted on in the English war, and it is permissible to doubt whether Cromwell would have acted on it on this occasion, if the defenders had been others than 'Irish Papists,' as he scornfully called them. The memory of the Ulster massacre of 1641, not merely as it really was, but accompanied by all the exaggerations to which it had been subjected by English rumour, was ever present to his mind, and he regarded every Irishman in arms, not as an honourable antagonist, but as either a murderer or a supporter of murderers.