This latter task was set about energetically, as soon as the winter was past, by the three princes who had specially taken in hand the suppression of the revolt, Archbishop Richard of Trier, Prince Ludwig of the Pfalz, and Count Phillip of Hesse. In February, Sickingen's second son, Hans, was taken prisoner, and shortly after the Castle of Wartenberg was captured. An armistice which Sickingen had asked for in order that the reinforcements he expected might have time to arrive, was refused, since the princes saw that their only chance of immediately crushing his power was to attack him at once. Towards the end of April a large army of cavalry, infantry, and siege artillery was called together at Kreuznach, not far from Sickingen's Castle of Ebernburg. Franz, however, was no longer there. He appears to have left Ebernburg for his strongest fortress at Landstuhl some weeks previously, though how and when is uncertain. Here he hoped to be able to hold out for at least three or four months, by which time his friends could deliver him; and when the army of the three princes appeared before the castle he sent back a mocking answer to their summons to surrender, to the effect that he had new walls and they had new guns, so they could now see which were the stronger. But Sickingen had not realised the power of the new projectiles; and in a week after the opening of the bombardment, on the 29th of April, the newly-fortified castle on which he had staked all his hopes was little better than a defenceless heap of ruins. In the course of the bombardment Franz himself, as he stood at an embrasure watching the progress of the siege, was flung against a splintered joist, owing to the gun-stand against which he was leaning being overturned by a cannon shot. With his side torn open he was carried down into a dark rocky vault of the castle, realising at last that all was lost. "Where are now," he cried, "my knights and my friends, who promised me so much and who have performed so little? Where is Fürstenberg? where Zollern? where are they of Strassburg and of the Brotherhood? Wherefore, let none place their trust in great possessions nor in the encouragements of men." It must be alleged, however, in their excuse, that his friends doubtless shared Franz's confidence in the impregnability of the Landstuhl, and were not aware of the imminent straits he had been in since the beginning of the attack. The messenger he had sent to the distant Fürstenberg had been captured by the army of the allied princes; Zollern knew of the need of his leader only with the news of his death; Hutten's efforts to obtain help in Switzerland had been in vain.