The contest between the Houses and the Crown had cost England her last possessions across the Channel. As York marched upon London Charles closed on the fragment of the duchy of Guienne which still remained to the descendants of Eleanor. In a few months all was won. Bourg and Blaye surrendered in the spring of 1451, Bordeaux in the summer; two months later the loss of Bayonne ended the war in the south. Of all the English possessions in France only Calais remained; and in 1452 Calais was threatened with attack. The news of this crowning danger again called York to the front. On the declaration of Henry's will to resist all change in the government the Duke had retired to his castle of Ludlow, arresting the whispers of his enemies with a solemn protest that he was true liegeman to the king. But after events show that he was planning a more decisive course of action than that which had broken down with the dissolution of the Parliament, and the news of the approaching siege gave ground for taking such a course at once. Somerset had been appointed Captain of Calais, and as his incapacity had lost England Normandy, it would cost her--so England believed--her last fortress in France. It was said indeed that the Duke was negotiating with Burgundy for its surrender. In the spring of 1452 therefore York again marched on London, but this time with a large body of ordnance and an army which the arrival of reinforcements under Lord Cobham and the Earl of Devonshire raised to over twenty thousand men. Eluding the host which gathered round the king and Somerset he passed by the capital, whose gates had been closed by Henry's orders, and entering Kent took post at Dartford. His army was soon fronted by the superior force of the king, but the interposition of the more moderate lords of the Council averted open conflict. Henry promised that Somerset should be put on his trial on the charges advanced by the Duke, and York on this pledge disbanded his men. But the pledge was at once broken. Somerset remained in power. York found himself practically a prisoner, and only won his release by an oath to refrain from further "routs" or assemblies. [Sidenote: Loss of Guienne]