It is assumed that this city occupies the site of Aquincum, mentioned in the “Itinerary of Antoninus.” During the Hungarian monarchy Buda was the residence of the kings, by whom, particularly Matthias the Great, it was extended and embellished. Under Suleiman the Magnificent the Turks took it in 1526, but in the following year it was retaken. In 1529 it again fell into the hands of the Turks and remained in their possession until 1686, when it was finally retaken by Charles of Lorraine and, in 1784, again made the seat of government. Buda has been besieged no fewer than 20 times in the course of its history. The last siege took place in May 1849, when the Hungarian army under Görgey had driven the Austrian troops back to the western frontier of the kingdom. With regard to further operations, two plans were discussed: first, to extend the advantages gained by vigorously pursuing the enemy onto his own soil, to disperse his forces before the Russians, who were at the time marching against Hungary, could come up, and to attempt to bring about a revolution in Vienna; or, to remain on the defensive before Komorn and detach a strong corps for the siege of Buda, where the Austrians had left a garrison on their retreat. Görgey asserts that Kossuth and Klapka insisted on the latter plan, but Klapka protests that he knows nothing of Kossuth having sent such an order, and denies ever having himself advised this step. On comparing the written statements of Görgey and Klapka, we must, however, confess that it still remains very doubtful upon whom the blame for the march on Buda falls, and that the proofs adduced by Klapka are by no means convincing. Görgey also writes that his decision was further determined by the total lack of field artillery ammunition and other supplies, and by his own conviction that the army would have refused to cross the frontier. At any rate, all offensive movements were stopped, and Görgey marched upon Buda with 30,000 men. By this step the last chance of saving Hungary was missed. The Austrians were given the opportunity to recover from their defeats, to reorganise their troops, and after six weeks, when the Russians appeared on the frontiers of Hungary, they again advanced with a strength of 127,000 men, while two reserve corps were still in the process of formation. Thus the siege of Buda forms the turning point of the Hungarian war of 1848/1849, and if there ever really were treasonable relations between Görgey and the Austrians, they must have taken place about this time.

The fortress of Buda was but a feeble remnant of that old stronghold of the Turks, in which they had so often repulsed all attacks of the Hungarian and imperial armies. The ditches and ramparts had been levelled, and only the main ramparts remained, structures of considerable height faced with masonry. In its general outlines the fortress formed a rectangle, the sides of which were broken more or less irregularly, thus allowing a fairly effective flanking fire. A newly erected entrenchment led from the east side down to the Danube and protected the waterworks by which the fortress was supplied with water. The garrison, under Major-General Hentzi, a brave and resolute officer, consisted of four battalions, about one company of sappers, and the requisite proportion of gunners. Seventy-five guns were mounted on the ramparts. After Görgey had completed the investment of the city and a short cannonade had been carried on with heavy field guns, he summoned the garrison to surrender. This being refused, he ordered Kmety to storm the waterworks. Under cover of the fire of all available guns, his column advanced, but the artillery of the entrenchment, which swept its line of march, soon drove it back. It was thus proved that a direct attack would never lead to the capture of the place, and that an artillery attack was indispensable first to batter a practicable breach. However, no heavier guns than twelve-pounders were available, and even for these ammunition was lacking. After some time, however, four twenty-four-pounders and one eighteen-pounder, and afterwards six mortars, arrived from Komorn. A breach battery was established on a hill, 500 yards from the north-west angle of the rampart, and on 15 May opened fire. Before this day, Hentzi had, without any provocation and without any possibility of deriving any advantage from this proceeding, bombarded the city of Pest. On the 16th the breach was opened, though scarcely practicable, but Görgey nevertheless ordered the assault for the following night. One column was to storm the breach, two others to scale the ramparts, and a fourth under Kmety to take the waterworks. The assault was unsuccessful at all points. The artillery attack was resumed. While the breach battery completed its work, the palisades round the waterworks were shot away by twelve-pounders, and the interior of the fortress was bombarded. Mock attacks were made every night to harass the garrison. Late in the evening of the 20th a further assault was prepared. The four columns and their objectives remained the same, and before daybreak on the 21st they advanced upon the fortress. After a desperate struggle, in the course of which Hentzi himself directed the defence of the breach and was mortally wounded, the 47th Honvéd battalion took the breach; it was followed by the 34th, while Kmety stormed the waterworks and the troops of the 3rd army corps under Knezich scaled the ramparts near the Vienna Gate. A fierce struggle ensued inside the fortress, but the garrison soon surrendered. Out of 3,500 men, about 1,000 were killed, the remainder taken prisoners. The Hungarians lost 600 men during the siege.