After the victory of Tenchebrai the whole of Normandy fell into the hands of Henry. Rouen, the capital, submitted without resistance to the conqueror, and the town of Falaise capitulated after a siege of short duration. Among the prisoners taken at Falaise was William, the son of Robert and Sibylla. Some feeling of pity seems to have entered the breast of the king when his nephew, then a child of five years old, was brought before him. He committed the prince to the care of Hélie de St. Saen, a Norman nobleman of high character, who had married a natural daughter of Robert. Soon afterwards, however, Henry attempted to secure the person of his nephew, and sent a body of troops to the castle of St. Saen for that purpose. Hélie, who feared some evil intention on the part of the king, effected his escape, and carried his young charge to the court of Louis VI., King of France. On the way Hélie passed some time at the courts of the most powerful Norman barons, and at that of Fulk, Count of Anjou, by whom, as well as by Louis, the prince was received with kindness and protection. He was brought up in the palace of the French king, who, as he grew up, presented him with horses and the harness of a knight, while Fulk promised to give him his daughter Sibylla in marriage. Louis, who dreaded the power of the King of England, saw the advantage he might obtain by supporting the legitimate claims of William Clito, or William of Normandy, as he was afterwards called. In the name of the young prince, he entered into a league with the chiefs of some of the neighbouring states, among whom was the Count of Flanders. Henry was attacked at various points along the frontiers of Normandy, and some of his fortresses and towns were taken. At the same time, many Norman barons, who were secretly attached to the cause of Duke Robert, engaged in a conspiracy against Henry. At length the king succeeded by policy in dissolving the league against him. A treaty was signed, by which the estates of Hélie de St. Saen were given to Fulk of Anjou, to whose daughter, Matilda, Henry agreed to marry his own son, William. The contract of marriage between Sibylla and the son of Robert was broken off, and the cause of the latter was no longer to be supported by the Count of Anjou. William of Normandy retired to the court of Baldwin, Count of Flanders, who was one of the warmest supporters of his cause. Having brought these negotiations satisfactorily to an end--for which purpose he had spent two years in Normandy--Henry returned to England. The sums expended by the king in procuring the submission of the friends of William were obtained by heavy burdens and exactions from the people of England. Each year is described as being attended with its peculiar calamity, and in the year 1110 the sufferings of the people were heavy, "caused by the failure of the crops and the taxes demanded by the king for the dowry of his daughter."[25]