War was at last declared by France against Great Britain on the 20th of March 1744, and a counter-declaration was made by the latter country on the 29th of the same month; thus these two powers, from auxiliaries, now became principals in the contest. [Sidenote: 1745.] In January 1745, the Emperor Charles VII. died at Munich, and Francis, Grand Duke of Tuscany, consort of Maria Theresa, became a candidate for the imperial crown; this circumstance changed the aspect of affairs in Germany, and led to the re-establishment of the House of Austria in the imperial dignity. In July Prince Charles Edward, eldest son of the Pretender, arrived in Scotland, and being joined by several clans, obtained some advantages; but after advancing as far as Derby, he retreated towards the north in December following. [Sidenote: 1746.] The hopes of the Pretender were annihilated by the battle of _Culloden_ on the 16th of April 1746, and part of the military force of the kingdom becoming available for other services, an expedition proceeded against the coast of Brittany. Sixteen sail of the line under Admiral Lestock, and eight frigates, conveying five thousand troops (of which the THIRTY-NINTH formed part), exclusive of Marines, under Lieut.-General St. Clair, sailed from Plymouth on the 14th of September, in order to make an attack on _Port L’Orient_, the principal station for the French East India Company’s shipping and stores. The troops landed in Quimperlay Bay on the morning of the 20th of September, and marched on the following day in two columns against _Plymeur_, which surrendered, and on the following day advanced to within a mile of _Port L’Orient_. Some affairs took place between the 21st and 26th of September, and the town was cannonaded; but the enemy having assembled a formidable force, it was determined to withdraw the troops, and they were accordingly re-embarked. The British troops landed on the peninsula of _Quiberon_ on the 4th of October, and captured a fort mounting eighteen guns; and after destroying all the forts and guns, together with those on the islands of Houat and Hedic, the force was re-embarked, sailed for England, and arrived at Spithead on the 26th of October. [Sidenote: 1747.] During the years 1747 and 1748, the regiment again served as _Marines_ on board the fleet. [Sidenote: 1748.] On the 7th of October 1748, the Treaty of Aix-la-Chapelle was signed, which terminated the war, and the regiment was again stationed in Ireland, where it remained upwards of five years. [Sidenote: 1751.]