The brave Hungarian nobles now rose in arms, and old Count Palfy marched at the head of 30,000 men to relieve Vienna, the Governor of which, Marshal Kevenhüller, had only 12,000 men to resist the three armies of France, Prussia, and Bavaria, while the Marshals Neuperg and Brown covered the roads to Bohemia with 20,000 men, as a protection against the kingdom of Bavaria. In all the operations of the Austrians, during the many encounters and severe campaigns of 1742-3, Count Brown commanded the vanguard or first division, and always with honour.
Prince Charles of Lorraine having succeeded Marshal Neuperg in command of the army, encountered the enemy near Braunau, and a desperate, but drawn battle (in which his forces suffered most) was fought, while Prince Lobcowitz, on marching from Bohemia, drove the French from all their posts and garrisons in the Upper Palatinate. Then the combined forces of the Prince, Brown, and Lobcowitz, forced those of Marshal Broglio to abandon their strongly intrenched camp at Pladling, on the Danube, and to fall back in confusion on the Rhine, while the irregular horse, Croats, Pandours, and Foot Talpaches, harassed their rear-guard, and exterminated the stragglers.
In this expedition Count Brown seized Deckendorf at the head of the vanguard, captured a vast quantity of baggage, and obliged the French, after immense slaughter, to abandon the banks of the Danube, which the whole Austrian army, under the Prince of Lorraine, passed in security on the 6th of June.
On this spot a pillar was afterwards erected, bearing, in the following inscription, an honourable testimony to the valour of the Irish hero:—
"Theresiæ Austriacæ Augustæ Duce Exercitus,
Carlo Alexandro Lothairingico,
Septemdecim, superatis hostilibus villis,
Captoque Deckendorfio, renitendibus undis,
Resistentibus, Gallis,
Duce exercitus Ludovico Borbonio Contio
Transivit hic Danubium,
Ulysses Maximilianus Brown, Campi Marashalus,
Die 5o Junii," A.D. 1743.
When Marshal Broglio reached Donawert, in the Swabian circle, he was joined by 12,000 men, under the warlike Maurice Count de Saxe, afterwards Marshal General of France and Duke of Courland; but finding his main body almost destroyed, instead of hazarding a battle, he retreated before Prince Charles and Brown to Heilbron, and there abandoning to them his artillery and baggage, retired with greater precipitation to Prague.
Lorraine followed, and encamped in sight of them, along the hills of Girisnitz. The French marshals offered to surrender Prague, Egra, and all their captures in Bohemia, provided they were permitted to march home with the honours of war. These offers were rejected with disdain; Prague was invested on all sides, and though the Marshal de Maillebois marched to its relief, he achieved nothing, for the Austrians possessed all the passes of the mountains, and he was compelled to retreat as a fugitive, harassed and galled by the troops of Prince Charles, who left Prince Lobcowitz to watch the motions of the Dukes of Belleisle and Broglio in the beleaguered city.
The latter of these marshals fled from his command in the disguise of a courier; the former abandoned the city in a dark and cold December night, and, with 14,000 men and 30 guns, made his way towards Alsace, enduring unheard-of miseries; 900 men whom he left behind him surrendered at discretion; and thus again the ancient capital of Bohemia reverted to the House of Austria, which, however, lost the Duchy of Silesia by the treaty of Breslau, which ceded it for ever to the kingdom of Prussia.
In the year 1743 Count Brown was sent by his Imperial Mistress to Worms as her plenipotentiary to George II. of Great Britain, with whose ministers he spared no pains to arrange the important alliance between the Courts of London, Vienna, and Turin. On this service he acquitted himself with an ability no way inferior to the courage he had displayed in so many fields.
The arena of his next service was again in Italy, where the Austrian forces were still fighting against the Spaniards, and pursuing the old war between the houses of Bourbon and Hapsburg.