In 1730 he served in the expedition to Corsica, and by his bravery and example contributed greatly to secure the capture of Callansara, where he was severely wounded in the thigh. This successful expedition caused a rumour that the island was to be erected into a kingdom for the Chevalier de St. George--James VIII. of the Scottish Jacobites; and George II., on being bribed by the Genoese, prohibited his English subjects from furnishing any assistance to the troops or inhabitants. In 1732, Count Brown was made Chamberlain of the Austrian Empire: and in 1734 was appointed full colonel of infantry, and Italy was the next scene of his service. France had resolved on humbling the overweening power of the House of Hapsburg; the venerable Marshal Villars crossed the Alps, and with a combined army of French and Spaniards, burst into Milan, overran Austrian Lombardy, and carrying victory wherever he marched, in two months' time left only Mantua under the flag of Charles VI. The latter made strenuous efforts to protect himself--to secure the passage of the Rhine against the Marshal Duke of Berwick on one hand, and to recover his power in Italy from Villars on the other. The Diet voted him 120,000 men; the Count de Merci marched 6000 of these to protect the important fortress of Mantua; and with a force increased to 60,000 soldiers, drew towards the head of the Oglio and Po. Leaving his young wife at the court of Vienna, Count Brown accompanied this force with his regiment of German infantry; and it was among the first of those brave battalions which effected the arduous passage of the Po near Santo Benedetto, where the Count de Merci so boldly and skilfully surprised the French troops, and drove them back at the bayonet's point, with the loss of all their ammunition, baggage, and the cities of Guastalla, Novella, and Mirandola, of which he immediately took possession.