In the meantime the suspicions of the Viennese had been increasing, and on the 29th of September Dr. Löhner, one of the original leaders of the March movement, publicly denounced Latour for his intrigues with Jellaciç. These intrigues had now been placed beyond a doubt by certain letters which had fallen into the hands of the Hungarian Ministry. Pulszky, who was at this time in Vienna, took the opportunity to publish these letters in the form of a placard, while he complained to Latour of the permission given to Jellaciç to raise recruits in Vienna, and threatened, if these proceedings continued, to excite a revolution in which the Viennese Ministers would be hung from lamp-posts. There were, indeed, revolutionary elements enough in Vienna at this time. The friendship between the workmen and the students had led to the formation of a special workman's Sub-Committee under the Committee of Safety. This body actually undertook to find employment for all who were out of work, and even to pay them wages while they were out of work. This offer naturally caused a rush of workmen to Vienna, from all parts of the Empire. The attempt to sift and regulate the claims for employment led to new bitterness; and demands for impossibly high wages provoked rebuffs, which were answered by threats of violence. The Ministry tried to induce the workmen to leave the city, by urging them to join the army in Italy; but the students defeated this attempt by reminding the workmen that the war in Italy was a war against liberty. The suspicions of the Ministers were now excited, not only against the workmen, but against the students; and, after a riot in the latter part of August, the Committee of Safety had been dissolved, and the lecture-rooms of the University closed. But this repression, far from weakening the bitterness in Vienna, only drew closer the links between the poorer students and the workmen; for, while the richer students left the city, the poorer ones, finding it difficult to support themselves after the closing of the lecture-rooms, were subscribed for by the workmen. Thus then the suspicions roused by the intrigues of Latour were strengthened considerably by the general condition of Vienna at this period.

Latour, however, was resolved not to yield. The defeats which Jellaciç was experiencing in Hungary only made it the more necessary that those who sympathized with him should send him help; and on the 5th of October the news spread through Vienna that an Austrian regiment was about to march to Hungary to the assistance of Jellaciç. The students went to the head-quarters of one of the grenadier regiments, and urged them not to join in the march. An officer, who arrested one of the students, was attacked and wounded; and when one of the grenadiers, who had been wounded in a quarrel, was sent to his barrack, his comrades seemed to consider it as a kind of arrest, and demanded his surrender. The National Guard joined in this demand; and thus a state of confusion arose which made it easy for the students and the workmen to hinder the march of the regiments which were starting for Hungary. An Italian battalion refused to proceed further, and the march was hindered for that day. But General Auersperg, who commanded the forces in Vienna, was resolved to continue the attempt; and so, on the following day, the soldiers were despatched to the station which lies beyond the Tabor bridge. But, when they arrived on the bridge, they found that the students and the National Guard were before them, and that the barriers had been closed against them. Auersperg was alarmed at this resistance, and recalled the troops; but collisions had by this time taken place between the soldiers and the people in other parts of the town; and a fierce fight was raging in the Stephansplatz, and even in the church itself.

Then suddenly there rose the cry "Latour is sending us the murderers of the 13th of March;" and a rush was made towards the office of the Ministry of War. Fears had already been entertained by several members of the Assembly, that a personal attack would be made on Latour; and Borrosch, one of the German Bohemian members, Smolka, the Vice-President of the Assembly, Dr. Goldmark, and others, hastened to protect Latour from the vengeance of the crowd. Borrosch, with the same humane ingenuity which Lafayette had shown on a similar occasion, promised that Latour should have a formal trial, if the crowd would spare him. The crowd cheered Borrosch and his friends; and many of them promised that they would protect Latour's life. Borrosch rode off, supposing Latour to be safe; but Dr. Fischhof, feeling that matters were not yet secure, persuaded several members of the National Guard to act as special protectors to Latour; and as the best means of effecting this object, some thirty or forty of them undertook to arrest him. But the excitement of the crowd had been roused anew, and they burst into the War Office. Smolka then entreated Latour to resign. The Minister consented; but the passions of the crowd would not be appeased. The unfortunate man attempted to hide from their pursuit: but they dragged him from his hiding-place, and thrust aside his defenders. Fischhof warded off the first blow that was aimed at him. A student, named Rauch, attempted also to protect him; but all was in vain; and he was dragged down the staircase and into the square in front of the War Office. With his white hair floating about him, he was lifted on to the lamp-post which then stood in the square. He struggled against his enemies, and compelled them to drop him once; but again he was lifted on to the post, and this time the hanging was completed, the crowd tearing his clothes from his body and dipping their handkerchiefs in his blood. This outburst of savagery, instead of satisfying the fury of the people, had quickened their thirst for blood; and their desire for vengeance was now turned against the Bohemian Deputies. Strobach, who had been chosen President of the Assembly, had objected to hold a sitting at all on that day, declaring that executive rather than legislative functions were needed just then. For this refusal some of the members wished to prosecute him; and armed men appeared in the gallery of the Assembly threatening violence to the Bohemian deputies. Those deputies, finding that they could no longer deliberate freely, soon after fled from the city, and issued from Prague a protest against the Reign of Terror, which they declared to be dominating Vienna. In the meantime Ferdinand, having consented, on the day of Latour's death, to the formation of a Democratic Ministry, fled, on the next day, from Vienna to Schönbrunn, and shortly afterwards to Innspruck; and he soon notified his feelings to the Viennese by a proclamation in which he too denounced the reign of violence in Vienna.

Hardly had the Viennese recovered from the surprise caused by the flight of their Emperor, than they heard that Jellaciç, having abandoned his hope of conquering Hungary, was marching against Vienna. General Auersperg, who had withdrawn his troops to the Belvedere after the collision between the soldiers and the people, was still assumed by the Viennese to be in some degree favourable to their cause; and they entreated him to repel the attack of Jellaciç, and to call for help from the Hungarians. Auersperg, however, rejected this proposal, withdrew his troops secretly from the city, and, on October 11, openly joined Jellaciç.

The Assembly were now anxious to appeal to the Frankfort Parliament for help, and entreated them to send representatives to Vienna. Robert Blum, who had grown weary of the state of affairs in Frankfort, and who believed that the only remaining hope for Germany was in Vienna, consented, in company with four others, to accept this embassy. The Parliament in Vienna still imagined that they could keep within legal forms; but this desire irritated those fiery politicians who felt that the struggle was now on a revolutionary footing; and they therefore desired to overthrow the Assembly, and to establish a more determined body in its place. But Blum, who had been accustomed to hold in check the violent members of his own party in Frankfort, supposed that, in Vienna also, he was bound to resist revolutionary methods; and, though he was ready to encourage the Viennese in the defence of their city, he objected to the proposal for the violent dissolution of the Assembly, on the ground that such a proceeding would give an excuse to the tyrants for a dissolution of the Frankfort Parliament.

A man of much more importance in such a siege than Robert Blum could be, arrived about the same time in Vienna. This was Joseph Bem, a Galician of about fifty-three years of age, who had served in Napoleon's expedition to Russia, and had greatly distinguished himself as colonel of the Polish artillery at the battle of Ostrolenka. He had also commanded the Polish artillery in the insurrection of 1830, and had attempted to organize a Polish legion, for the help of the Portuguese, during their struggle against the Absolutist party. He had been wounded in one of these wars, was obliged to use a staff in walking, and was small and delicate in his appearance. He had gained both friends and enemies in Poland, and was known for his strong democratic sympathies. Although he was not appointed to the official headship of the National Guard, he soon became the centre and life of the defence. But he found that the men with whom he had to act did not understand the position in which they were placed; for, when he attempted to urge the National Guard to march out against the army of Jellaciç, they twice refused to follow him, on the ground that they were only intended for the defence of the city.

And, if the rulers of Vienna were feeble in their attitude towards their enemies, they were not less feeble in their treatment of the one people, from whom they might have expected help in this emergency. The advance of Jellaciç against Vienna had naturally increased the sympathy of the Magyars for the Viennese, and Pulszky urged the latter to summon the Hungarian army to their rescue. This formal invitation was the more necessary because the Hungarian officers were in many cases confused in their minds as to their strict legal duty in this war. Archduke Stephen, the Count Palatine of Hungary, after professedly assuming the command of the army, had suddenly fled from the country, and thus weakened the legal position, both of his subordinate officers, and of the Hungarian Diet, of which he was the nominal head. Ferdinand had repeated his former dissolution of the Diet in a proclamation of the 20th October; Prince Windischgrätz, professing to act in the name of the Emperor, issued a declaration from Prague forbidding the Hungarian officers to fight against Jellaciç; and soon after, followed up this proclamation by marching against Vienna. General Moga, the Commander-in-Chief of the Hungarian forces, hesitated to resist the Imperial orders; but, whilst the generals were debating among themselves, Kossuth arrived in the Hungarian camp to urge them to advance. After some delay his influence prevailed; and on October 28 began the march of the Hungarian army for the relief of Vienna.

In the meantime, all those in Vienna, who really cared to save it, were trying to rouse their fellow-townsmen to action. Robert Blum made an address to the students in favour of making "no half-revolution, but a complete change of the system;" and on the 25th October, three days before the Hungarians had begun their march, Bem had succeeded in persuading the National Guard to make their sortie. But confusion followed this attempt; some of the Guard fled; others were mistaken in the darkness for enemies, and fired on by their comrades. Bem's horse was killed under him, and he was compelled to retreat. Windischgrätz, who had now been appointed to the complete command of the besieging force, demanded the surrender of "the Polish emissary Bem, who in a quite uncalled-for manner, had mixed himself up in the affairs of Vienna." This recognition of the independence of the Polish provinces of the Austrian Empire was not accepted by the Viennese; nor did they consent to surrender any of the other people who were demanded by Windischgrätz. Bem roused the soldiers again to the defence, and drove them to their work with abuse. The Students' Legion distinguished itself by its courage; and some of the workmen seconded them bravely. But Messenhauser, the official leader of the National Guard, declared that the struggle was hopeless, and urged the people to yield.

Many were now disposed to abandon the defence; when suddenly, on October 30, there arose a cry that the Hungarians were approaching. Messengers went up the high tower of St. Stephen's Church, and looked out towards the plain of Schwechat, where the Hungarians and Austrians had at last joined battle. The Viennese had been advised by their Hungarian friends to tear up the railway lines; but they neglected this precaution; and thus Windischgrätz had been able to send more troops to Schwechat. But the great weakness of the Hungarians was due to the hesitation of General Moga, and to the want of confidence felt in him by his subordinate officers. Troops were ordered to advance, and then suddenly to halt, without any apparent reason; several of the new recruits ran away; and at last a general panic seized the army, and they fled before the Austrians, continuing to retreat, even after the enemy had ceased to pursue them.

The rumours of Hungarian help had encouraged some of the Viennese to oppose the surrender of their city; and this opposition was continued even after the defeat of the Hungarians had been officially announced. This division of opinion between the leaders and a great part of the people, led to riots in various parts of the town. Under these circumstances, Windischgrätz refused to accept the peaceable surrender offered by the leaders, and, instead, bombarded the town, and then entered it, while it was still on fire. Bem managed to escape; and so did three of the representatives of the Frankfort Parliament; but Blum and Fröbel were arrested. The latter was discovered to have written a pamphlet, which implied a desire to maintain the unity of the Austrian Empire; and, on this ground, he was set free. But Blum was proved to have acted as a captain of one of the corps of the National Guard, during the defence; his speech to the students, about the complete change of system, was supposed to imply a desire for a Republican movement; and so on the 8th November he was condemned to death, and on the 9th he was shot.