He was born in Spain, whither his father had followed the Duke of Berwick, in 1731, and after receiving the usual rudiments of education, commenced his military career at the early age of sixteen, in the brave old Irish regiment of Ulster infantry, then in the service of his Most Catholic Majesty Ferdinand VI., who had succeeded his father, Philip Duke of Anjou, on the Spanish throne, in the preceding year, 1746.
Francis Anthony Lacy served with this regiment in the Italian campaign of 1747, which was undertaken to advance the claims of the Spanish Bourbons to the crowns of Naples and Sicily, and to the Duchy of Milan, which had been claimed by Philip V., as successor to the House of Austria; while he also demanded Parma, Placentia, and Tuscany, in right of his queen, though he had been obliged to relinquish them all by the solemn treaty of Utrecht; but such is the faith kept by princes.
The Irish regiment of the young Count Lacy was with the army of the Count de Gages, the Spanish commander-in-chief, who had then under his orders the combined armies of Spain and Naples. Genoa had revolted against the Austrians; Marshal Boufflers had entered it at the head of 4500 Frenchmen, and thus encouraged, the Genoese resolved to die, rather than submit to the tyranny of the House of Hapsburg, whose armies made incredible exertions to recover it. Then ensued the passage of the Var by the Marshal Duke de Belleisle; the storming of Montalbano and other places; the investment of Genoa by the Austrians and Piedmontese, and other operations of that extensive campaign, in which le Régiment Irlandais d'Ultonie Infanterie bore a most prominent part, more so, perhaps, than their enemies relished, till the naval victories of the British Admirals Anson and Warren in the East Indian Ocean, and those of Fox and Hawke elsewhere, forced Louis XV. and his allies to listen to those proposals by which peace was secured to Europe by the treaty of Aix-la-Chapelle, on the 7th October, 1748.
Passing through all the successive grades with honour to himself, Count Lacy, in his thirty-first year, obtained the colonelcy of the Ulster regiment, and, at its head, served in the war against Portugal in 1762, when Charles III. of Spain added to the calamities of his unfortunate neighbour Don Joseph, by invading his small dominions with a powerful army, which threatened with still further destruction his hapless city of Lisbon—then recently ruined by the great earthquake. One Spanish column, under the Marquis de Sarria, entered Portugal on the north; a second, under the Count O'Reilly, took Chaves; a third entered by Beira and spread along the Tagus. This wanton invasion was suggested to Spain by France, as a means of insulting an ally of their common foe—Britain—and also of extending by conquest the power of the Houses of Bourbon.
Britain supplied Portugal with arms, ammunition, and 10,000 men, under Brigadier General Burgoyne, who skilfully co-operated with the Count de la Lippe, a German, and with General Forbes, a Scot, who commanded the army of Don Joseph. Two regiments of Catholics were raised in Ireland especially for this service, and these are still existing in the British line.
In all the operations of this war Lacy acquitted himself with the greatest honour.
In 1780, he was appointed Commandant of the Spanish Artillery, and as such was employed at the famous Siege of Gibraltar, and was present with the army which, under the Duke de Crillon (the conqueror of Minorca), made "the last desperate and unparalleled efforts" to restore the key of the Mediterranean to the hands of King Charles III.
General Elliot of Stobs, in Midlothian, with 7000 men, valiantly defended the rock against 40,000 soldiers who assailed it by land with 200 pieces of cannon: and against the combined fleets of France and Spain, forty-seven sail of the line, seven three-deckers (the strongest that had ever been built), eighty gunboats, and a swarm of frigates and smaller vessels, which opened a shower of shot from 400 pieces of cannon against him.