But it was not in England only that the king showed his strength and activity. Vile as he was, John possessed in a high degree the political ability of his race, and in the diplomatic efforts with which he met the danger from France he showed himself his father's equal. The barons of Poitou were roused to attack Philip from the south. John bought the aid of the Count of Flanders on his northern border. The German king, Otto, pledged himself to bring the knighthood of Germany to support an invasion of France. But at the moment of his success in diplomacy John suddenly gave way. It was in fact the revelation of a danger at home which shook him from his attitude of contemptuous defiance. The bull of deposition gave fresh energy to every enemy. The Scotch king was in correspondence with Innocent. The Welsh princes who had just been forced to submission broke out again in war. John hanged their hostages, and called his host to muster for a fresh inroad into Wales, but the army met only to become a fresh source of danger. Powerless to oppose the king openly, the baronage had plunged almost to a man into secret conspiracies. The hostility of Philip had dispelled their dread of isolated action; many indeed had even promised aid to the French king on his landing. John found himself in the midst of hidden enemies; and nothing could have saved him but the haste--whether of panic or quick decision--with which he disbanded his army and took refuge in Nottingham Castle. The arrest of some of the barons showed how true were his fears, for the heads of the French conspiracy, Robert Fitzwalter and Eustace de Vesci, at once fled over sea to Philip. His daring self-confidence, the skill of his diplomacy, could no longer hide from John the utter loneliness of his position. At war with Rome, with France, with Scotland, Ireland, and Wales, at war with the Church, he saw himself disarmed by this sudden revelation of treason in the one force left at his disposal. With characteristic suddenness he gave way. He endeavoured by remission of fines to win back his people. He negotiated eagerly with the Pope, consented to receive the Archbishop, and promised to repay the money he had extorted from the Church. [Sidenote: John becomes vassal of Rome]