After an easy progress, during which several trifling places, the most important being St. Wendel, were taken, Franz with his army arrived on the 8th of September before the gates of Trier. He had hoped to capture the town by surprise, and was indeed not without some expectation of co-operation and help from the citizens themselves. On his arrival he shot letters within the walls summoning the inhabitants to take his part against their tyrant; but either through the unwillingness of the burghers to act with the knights, or through the vigilance of the archbishop, they were without effect. The gates remained closed; and in answer to Sickingen's summons to surrender, Richard replied that he would find him in the city if he could get inside. In the meantime Sickingen's friends had signally failed in their attempts to obtain supplies and reinforcements for him, in the main owing to the energetic action of some of the higher nobles. The Archbishop of Trier showed himself as much a soldier as a churchman; and after a week's siege, during which Sickingen made five assaults on the city, his powder ran out, and he was forced to retire. He at once made his way back to Ebernburg, where he intended to pass the winter, since he saw that it was useless to continue the campaign, with his own army diminishing and the hoped-for supplies not appearing, whilst the forces of his antagonists augmented daily. In his stronghold of Ebernburg he could rely on being secure from all attack until he was able to again take the field on the offensive, as he anticipated doing in the spring.
There is some doubt as to the events which occurred during this retreat to Ebernburg. Sickingen's adversaries asserted that not only did his army destroy churches and monasteries, but that the houses of the peasants in the surrounding country were plundered and burnt. His friends, on the other hand, maintain with equal vehemence that Sickingen and his followers confined themselves to wiping out of existence as many as possible of the hated ecclesiastical foundations.
In spite of the obvious failure of the autumnal campaign, the cause of the knighthood did not by any means look irretrievably desperate, since there was always the possibility of successful recruitments the following spring. Ulrich von Hutten was doing his utmost in Würtemberg and Switzerland to scrape together men and money, though up to this time without much success, while other emissaries of Sickingen were working with the same object in Breisgau and other parts of Southern Germany. Relying on these expected reinforcements, Franz was confident of victory when he should again take the field, and in the meantime he felt himself quite secure in one or other of his strong places, which had recently undergone extensive repairs and seemed to be impregnable. In this anticipation he was deceived, as will shortly be seen, for he had not reckoned with the new and more potent weapons of attack which were replacing the battering-ram and other mediæval besieging appliances.
The princes, meanwhile, were not inactive. Immediately after the abortive attack on Richard of Trier, Sickingen was placed under the ban of the Empire (Oct. 8), but although the latter had temporarily disbanded his army it was impossible for them to attack him at once. They therefore contented themselves for the moment by wreaking their vengeance on those of his supporters who were more easily to be reached. Albrecht of Mainz, whose public policy had been that of "sitting on the fence all round," was fined 25,000 gulden for his lukewarmness in supporting his colleague, the Elector of Trier. Kronberg, near Frankfort, which was held by Sickingen's son-in-law, Hardtmuth, was taken by a force of 30,000 men (?); Frowen von Hutten, the cousin of Ulrich, was driven from his Castle of Saalmünster and dispossessed of his estates, whilst a number of the smaller fry equally felt the heavy hand of the princely power. The chastisement of more distant adherents to the cause of the knighthood, like the Counts of Fürstenberg and Zollern and the knights of Franconia, was left over until the leader of the movement had been dealt with.
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.
Seeing that now all was over and he himself on the point of death, Sickingen wrote to the princes, requesting them to come and see him. The firing at once ceased, and negotiations were entered upon for the surrender of the castle. On the 6th of May Sickingen agreed to the articles of capitulation, which included the surrender of himself and the rest of the knights in the castle as prisoners of war, his other retainers giving up their arms and leaving the castle on the following day. The Landstuhl with all its contents was to fall, of course, into the hands of the besiegers. As Franz signed the articles, he remarked to the ambassadors: "Well, I shall not be long your prisoner".
On the 7th of May the princes entered the castle and were at once taken to the underground chamber where Franz lay dying. He was so near his end that he could scarcely distinguish his three arch-enemies one from the other. "My dear lord," he said to the Count Palatine, his feudal superior, "I had not thought that I should end thus," taking off his cap and giving him his hand. "What has impelled thee, Franz," asked the Archbishop of Trier, "that thou hast so laid waste and harmed me and my poor people?" "Of that it were too long to speak," answered Sickingen, "but I have done nought without cause. I go now to stand before a greater Lord." Here it is worthy of remark that the princes treated Franz with all the knightliness and courtesy which were customary between social equals in the days of chivalry, addressing him at most rather as a rebellious child than as an insurgent subject. The Prince of Hesse was about to give utterance to a reproach, but he was interrupted by the Count Palatine, who told him that he must not quarrel with a dying man. The count's chamberlain said some sympathetic words to Franz, who replied to him: "My dear chamberlain, it matters little about me. It is not I who am the cock round which they are dancing." When the princes had withdrawn, his chaplain asked him if he would confess; but Franz replied: "I have confessed to God in my heart," whereupon the chaplain gave him absolution; and as he went to fetch the host "the last of the knights" passed quietly away, alone and abandoned. It is related by Spalatin that after his death some peasants and domestics placed his body in an old armourchest, in which they had to double the head on to the knees. The chest was then let down by a rope from the rocky eminence on which stood the now ruined castle, and was buried beneath a small chapel in the village below.
The scene we have just described in the castle vault meant not merely the tragedy of a hero's death, nor merely the destruction of a faction or party. It meant the end of an epoch. With Sickingen's death one of the most salient and picturesque elements in the mediæval life of Central Europe received its death-blow. The knighthood as a distinct factor in the polity of Europe henceforth existed no more.
Spalatin relates that on the death of Sickingen the princely party anticipated as easy a victory over the religious revolt as they had achieved over the knighthood. "The mock Emperor is dead," so the phrase went, "and the mock Pope will soon be dead also." Hutten, already an exile in Switzerland, did not many months survive his patron and leader, Sickingen. The rôle which Erasmus played in this miserable tragedy was only what was to be expected from the moral cowardice which seemed ingrained in the character of the great Humanist leader. Erasmus had already begun to fight shy of the Reformation movement, from which he was about to separate himself definitely. He seized the present opportunity to quarrel with Hutten; and to Hutten's somewhat bitter attacks on him in consequence he replied with ferocity in his Spongia Erasmi adversus aspergines Hutteni.
Hutten had had to fly from Basel to Mülhausen and thence to Zürich, in the last stages of syphilitic disease. He was kindly received by the reformer, Zwingli of Zürich, who advised him to try the waters of Pfeffers, and gave him letters of recommendation to the abbot of that place. He returned, in no wise benefited, to Zürich, when Zwingli again befriended the sick knight, and sent him to a friend of his, the "reformed" pastor of the little island of "Ufenau," at the other end of the lake, where after a few weeks' suffering he died in abject destitution, leaving, it is said, nothing behind him but his pen. The disease from which Hutten suffered the greater part of his life, at that time a comparatively new importation and much more formidable even than now-a-days, may well have contributed to an irascibility of temper and to a certain recklessness which the typical free-lance of the Reformation in its early period exhibited. Hutten was never a theologian, and the Reformation seems to have attracted him mainly from its political side as implying the assertion of the dawning feeling of German nationality as against the hated enemies of freedom of thought and the new light, the clerical satellites of the Roman see. He was a true son of his time, in his vices no less than in his virtues; and no one will deny his partiality for "wine, women, and play". There is reason, indeed, to believe that the latter at times during his later career provided his sole means of subsistence.