But Edward's campaign against France proved utterly unsuccessful; his Netherland allies were of little use to him, King Philip refused to risk a battle in the field, and an attack on Cambray was defeated. Edward had to return to England to raise more money; while at home, he heard that a great French fleet had been collected for the conquest of Flanders and a subsequent attack on England. Hastily raising all the ships he could gather from London and the Cinque Ports, the king set sail to seek the enemy. He found them in harbour at the Flemish port of Sluys, and there brought them to action. They had chained their ships in three lines and built up barricades upon them; but, by pretending to fly, Edward induced them to cast loose and follow him, and, when they had got out to sea, turned and attacked. The English archery swept the enemy's decks, and then the king and his knights clambered up, and boarded vessel after vessel till well-nigh the whole French fleet was taken (1340). No such glorious day had been seen since Hubert de Burgh won the battle off Dover 120 years before. [Sidenote: =Contest with Parliament.=] The victory of Sluys freed England from the danger of invasion, but did nothing more. For when the king landed in Flanders, and pushed forward against France, he again failed to break through the line of strong towns that guarded Philip's frontier, and had to return home foiled. On coming to England he fell into a bitter strife with his Parliament, who were far from contented with the repeated checks in Flanders. Edward began by charging his failure on his ministers and dismissed them all, from the Chancellor and the Archbishop of Canterbury downwards, accusing them of having misappropriated the taxes. He announced that he would bring them to trial, and appointed a special commission for the purpose. This led to a vindication of the ancient right of trial by a man's equals, for John de Stratford, the archbishop, insisted on being tried in Parliament by the barons his peers, and carried his point against the king's strenuous opposition. He was of course acquitted, as nothing could be found against him. The Parliament only consented to grant the king fresh supplies when he swore (1) to let them appoint a committee to audit the accounts of the money; (2) to take no further _maltolts_ or tallages, but confine himself to the duly voted supplies; (3) to choose his ministers only with Parliament's consent, and make them answerable to Parliament for malfeasance in their office (1341). If these conditions had been kept, the crown would have been completely under control of the national council, but Edward shamelessly broke them when fortune turned in his favour. [Sidenote: =Edward invades Normandy.--Battle of Crécy.=]