The first and most obvious work which now lay before Henry was the conquest of England, and the plans which had been earlier formed for this object and deferred by these events were at once taken up. By the end of June the young bridegroom was at Barfleur preparing to cross the channel with an invading force. But he was not to be permitted to enjoy his new fortunes unchallenged. Louis VII in particular had reasons for interfering, and the law was on his side. The heiress Eleanor had no right to marry without the consent of her feudal suzerain. A summons, it is said, was at once served on Henry to appear before the king's court and answer for his conduct,[44] and this summons, which Henry refused to obey, was supported by a new coalition. Louis and Eustace were again in alliance, and they were joined by Henry's own brother Geoffrey, who could make considerable trouble in the south of Henry's lands, by Robert of Dreux, Count of Perche, and by Eustace's cousin Henry, Count of Champagne. Stephen's brother Theobald had died at the beginning of the year, and his great dominions had been divided, Champagne and Blois being once more separated, never to be reunited until they were absorbed at different dates into the royal domain. This coalition was strong enough to check Henry's plan of an invasion of England, but it did not prove a serious danger, though the allies are said to have formed a plan for the partition of all the Angevin empire among themselves. For some reason their campaign does not seem to have been vigorously pushed. The young duke was able to force his brother to come to terms, and he succeeded in patching up a rather insecure truce with King Louis. On this, however, he dared to rely enough - or perhaps he trusted to the situation as he understood it - to venture at last, in January, 1153, on his long-deferred expedition to recover his mother's kingdom. Stephen had begun the siege of the important fortress of Wallingford, and a new call for aid had come over to Normandy from the hard-pressed garrison.
In the meantime, during the same days when the divorce and remarriage of Eleanor of Aquitaine were making such a change in the power and prospects of his competitor for the crown, Stephen had made a new attempt to secure the possession of that crown firmly to his son Eustace. A meeting of the great council of the kingdom, or of that part which obeyed Stephen, was called at London early in April, 1152. This body was asked to sanction the immediate consecration of Eustace as king. The barons who were present were ready to agree, and they swore allegiance to him and probably did homage, which was as far as the barons by themselves could go. The prelates, however, under the lead of the Archbishop of Canterbury, - Henry of Winchester is not mentioned in this case, - flatly refused to perform the consecration. The papal prohibition of any such act still held good, and the clergy of England had been given, as they would recall the past, no reason to disobey the pope in the interests of King Stephen. The king, in great anger, appealed to force against them, but without avail. Temporary imprisonment of the prelates at the council, in a house together, even temporary confiscation of the baronies of some of them, did not move them, and Stephen was obliged to postpone his plan once more. The archbishop again escaped to the continent to await the course of events, and Stephen appealed to the sword to gain some new advantage to balance this decided rebuff. Then followed the vigorous siege of Wallingford, which called Henry into England at the beginning of January.
The force which Henry brought with him crossed the channel in thirty-six ships, and was estimated at the time at 140 men-at-arms and 3000 foot-soldiers, a very respectable army for that day; but the duke's friends in England very likely formed their ideas of the army he would bring from the breadth of his territories, and they expressed their disappointment. Henry was to win England, however, not by an invasion, but by the skill of his management and by the influence of events which worked for him here as on the continent without an effort of his own. Now it was that Ralph of Chester performed his final change of sides and sold to Henry, at the highest price which treason reached in any transaction of this long and favourable time, the aid which was so necessary to the Angevin success. Henry's first attempt was against the important castle of Malmesbury, midway between Bristol and Wallingford, and Stephen was not able to prevent its fall. Then the garrison of Wallingford was relieved, and the intrenched position of Stephen's forces over against the castle was invested. The king came up with an army to protect his men, and would gladly have joined battle and settled the question on the spot, but once more his barons refused to fight. They desired nothing less than the victory of one of the rivals, which would bring the chance of a strong royal power and of their subjection to it. Apparently Henry's barons held the same view of the case, and assisted in forcing the leaders to agree to a brief truce, the advantage of which would in reality fall wholly to Henry.