Some few years after the abortive rising of Ralf and Roger, the king found worse enemies in his own household. His eldest son and heir, Robert, began to importune him to grant him some of his lands to rule, and begged for the duchy of Normandy. But William was wroth, and drove him away with words of sarcastic reproof. The headstrong young man fled from his father's court and took refuge with Philip, the French king, William's nominal suzerain. Supported by money and men from France, Robert made war upon his father, and defeated him at the fight of Gerberoi (1079). Both father and son rode in the forefront of the battle. They met without knowing each other, and William was unhorsed and wounded by his son's lance. Only the courage of an English thegn, Tokig of Wallingford, who gave his horse to his fallen master, and received a mortal wound while helping him to make off, saved William from death. It must be added that Robert was deeply moved when he learnt how near he had been to slaying his own father, and then he immediately after sought pardon, and received it. But he had lost the first place in the king's heart, which was given to his second son William, whose fidelity was always unshaken. Robert was not the only kinsman of the Conqueror who justly incurred his wrath. His brother Bishop Odo angered him sorely by his cruel and oppressive treatment of Northumbria, and still more by raising a private army to make war over-seas; William seized him and kept him shut up in prison as long as he lived. [Sidenote: =Threatened Danish invasion.=] Disputes with foreign powers also arose to vex William's later years. In 1084, Cnut, King of Denmark, threatened to invade the island, and such a heavy _Danegelt_ was raised to pay the mercenary army which the king levied against him, that it is said that no such grievous tax had ever before been raised in England. Yet Cnut never came, being slain by his own people ere he sailed. Less threatening, but more perpetually troublesome than the danger of a Danish invasion, were William's broils with Philip of France, who even in time of peace was always stirring up strife. But Philip, though nominally ruler of all France, was practically too weak to cope with William, since his authority was quietly disregarded by most of the counts and dukes who owned him as liege lord. [Sidenote: =Domesday Book.=]