Little as he must have liked the service, Captain Loudon commenced a campaign in their ranks, in the war which ensued on Louis XV. and the King of Prussia leaguing together for the partition of the Austrian Empire. A French army under the Marshal Dukes de Belleisle and de Broglie, entered Germany, where the Bavarian Elector formed a junction with them; reduced Lintz, the capital of Upper Austria, and threatened Vienna. Kevenhüller recovered Lintz; the battle of Czaslau, in which the Pandours and Croats charged with such effect and fury was fought; Prague was besieged, and all northern Europe found itself engaged in a general strife.
At the head of his Pandours Baron Trenck acted the part of a bold partisan. He stormed the Isle of Rheinmarck, put its garrison to the sword, and with his own sabre slew the commandant, the Comte de Creveceur. Mentzel with four thousand Croats and Pandours broke into Lorraine and Luxembourg, where they committed terrible devastations.
In 1744, when Prince Charles of Lorraine forced his famous passage over the Rhine, Gideon Loudon led his company in the foremost boat, and was the first who landed on French ground; but in a skirmish with the advanced picquets of the French near Zabern, a city built on the summit of a rock, and defended by a strong castle of the Bishops of Strasburg, he was struck by a musket-ball when fighting bravely at the head of his men. It entered his right breast and came out behind near the shoulder-blade, and thus incapacitated him for farther service for some time. He fell—was taken prisoner, and conveyed to a neighbouring cottage. A few days afterwards the Austrian army advanced; the Pandours drove the enemy; Loudon was restored to liberty, and had the satisfaction of saving from pillage the dwelling of the peasant with whom he had found shelter and by whom he had been benevolently treated.
Meantime the King of Prussia, sick of his bloody victories, signed the treaty of Breslau, which filled France with consternation, and forced her marshals, Belleisle and Broglie, to retire towards Prague; but the close of 1745 saw tranquillity restored to Germany for a time.
Disgusted with the reckless regiment of Trenck, Loudon quitted it and returned to Vienna, where he resigned his commission and was preparing to leave the Austrian dominions in search of fortune elsewhere, when some of his military friends advised him to remain, and procured for him a majority in the regiment of Liccaner, which at that time was garrisoning a town on the Croatian frontier. His old corps the Pandours were disbanded, but were afterwards re-organized in 1750 as regular troops, and became of great service in the war of 1756, and in those of the first French Revolution.
This new appointment and its emoluments enabled him to espouse Clara de Hagen, the daughter of a brave Hungarian officer who resided at Pæsing. He was sincerely attached to this lady, and they had one child, a daughter, who died in infancy.
During ten years that he remained in the garrison towns of Croatia he spent all his leisure hours in perfecting his military education, and completing the study of fortification, geography, and geometry. He procured a vast number of maps and plans of fortified places, such as castles and barrier towns; and, as if he had some intuitive presentiment of the part he was yet to perform in the great game of war, he pored over them incessantly. Having once obtained a German map of unusual size, he spread it over the floor of his barrack-room, and sat down upon it, to pursue his study of it with greater ease, and was thus occupied when Madame Loudon entered.
"My dear major," said she, "still as ever, occupied by these horrid plans and perpetual studies!"
"Never mind my present labours," said he, cheerfully; "they will be of great service to me, my dear Clara, when I obtain the bâton of a field-marshal."
Madame Loudon laughed, for her husband was then eight-and-thirty, and the bâton of a marshal seemed yet to be a long way off.