The root of the Hundred Years' War, now just about to commence, must be sought in the affairs of Guienne, and not in any of the other causes which complicated and obscured the outbreak of hostilities. These, however, were sufficiently important in themselves. The most obvious was the aid which Philip VI. had given to the exiled David Bruce, when he was driven out of Scotland by Edward and his ally Baliol. The English king replied by welcoming and harbouring Robert of Artois, a cousin whom Philip VI. had expelled from France. He also made alliances with several of the dukes and counts of the Netherlands, and with the emperor Louis the Bavarian, obviously with the intention of raising trouble for France on her northern and eastern frontiers. Beginning of the war. It was Philip, however, who actually began the war, by declaring Guienne and the other continental dominions of Edward III. forfeited to the French crown, and sending out a fleet which ravaged the south coast of England in 1337. In return Edward raised a claim to the throne of France, not that he had any serious intention of pressing it--for throughout his reign he always showed himself ready to barter it away in return for sufficient territorial gains--but because such a claim was in several ways a useful asset to him both in war and in diplomacy. It was first turned to account when the Flemings, who had scruples about opposing their liege lord the king of France, found it convenient to discover that, since Edward was the real king and not Philip, their allegiance was due in the same direction whither their commercial interests drew them. Led by the great demagogue dictator, Jacob van Artevelde, they became the mainstay of the English party in the Netherlands. Edward III. and the French crown.