The reunion of Hainault and Flanders was, however, destined to be short-lived. Baldwin VI died in 1070, leaving his widow Richilda with two young children; Robert, her brother-in-law, rebelled against her. After his victory at Mont Cassel, where he defeated a French army sent by the king to Richilda's help, he left Hainault to his nephew and took possession of Flanders. Up to then, the counts had resided most of the time in the southern part of their possessions, where they had their richest domains. Robert the Frisian established his capital at Bruges, whose trade was beginning to develop rapidly, and which had opened relations with England and the Baltic countries. The fact that Robert's first possessions were in Holland might have influenced his choice, but the change marks, nevertheless, an important stage in the evolution of Flanders from a purely agricultural country into an industrial and commercial one. It looked at one time as if war was going to break out between England and Flanders, as the Conqueror, owing to his marriage, had some claims on the country. Robert, who had given his daughter in marriage to King Canute of Denmark, concluded an alliance with him, and even projected a combined attack on the English coast, which, however, never materialized. He proved an irreconcilable enemy to the German emperors, and entered into close relations with the Pope. His pilgrimage to Jerusalem, in 1083, added to his prestige, and the Emperor Alexis, who had received him with great pomp in Constantinople, asked his support against the Turks. The letter which the emperor addressed to him at the time, as to the "staunchest supporter of Christianity," and which was given wide circulation, had a considerable influence in preparing the first crusade, in which his son Robert II (1093-1111) took a prominent part under Godfrey of Bouillon. The rich and powerful Count of Flanders did not remain in the Holy Land, like the ruined Duke of Lotharingia. His home interests were far too important. He gave up the Danish policy of his father and allied himself to the King of France against the English kings, whose power was rapidly increasing. The French alliance stood him in good stead when, making a pretext of the struggle of the investitures and of his relationship with the Pope, he renewed his ancestor's claim upon the emperor's possessions. More successful than Baldwin IV, he succeeded in detaching the bishopric of Arras from Cambrai, and in spite of the obstinate resistance of Henry IV and Henry V, in obtaining the suzerainty over Cambraisis. [_POLICY OF FLANDERS_]