1812
In the meantime the war with France was approaching to a crisis; Napoleon Bonaparte had attained the summit of power, and the efforts of Great Britain were commensurate with the importance of the contest; the army was augmented, and in the autumn of 1811 a second battalion was added to the Twelfth regiment of four hundred and fifty-one officers and soldiers, into which the recruiting companies of the regiment were incorporated.
In the autumn of 1812, the second battalion proceeded to Ireland.
1813
In April, 1813, the first battalion embarked from Port Louis, for the island of Bourbon, where it was stationed nearly two years.
1814
1815
During this period the tyrannical power of Bonaparte had been overthrown, and the Bourbon dynasty restored to the throne of France. On the re-establishment of peace in Europe, the island of Bourbon was restored to the French monarchy, and in consequence of this arrangement the regiment embarked from St. Denis on the 3rd of April, 1815; the French soldiers, who arrived from Europe to take possession of the island, landing as the British went on board the ships prepared to receive them.
The Mauritius, or Isle of France, was retained by the British government, and the Twelfth foot having been selected to form part of the garrison of that valuable island, immediately proceeded thither.
Soon afterwards, Bonaparte quitted the island of Elba, in violation of his engagements, and regained the throne of France, when the powers of Europe took arms against the usurper, and his veteran legions were overpowered in the field of Waterloo by the allied army under Field Marshal His Grace the Duke of Wellington, on the 18th of June, 1815. To replace the losses of the British army at Waterloo, additional forces were sent to the continent, and the second battalion of the Twelfth regiment, which had returned to England a few months previously from Ireland, embarked for Flanders on the 27th of June, under the command of Colonel Julius Stirke; it landed at Ostend and advanced to Paris, where the campaign was terminated by the restoration of the Bourbon dynasty to the throne of France. Peace being again established in Europe, the battalion returned to England in December.
In June, 1815, the rifle company of the first battalion proceeded to Bengal, and formed part of a field brigade assembled for service; it, however, returned to the Mauritius in November.