William, fifth Earl of Seaforth, having engaged in the rebellion of 1715, was afterwards included in the acts of attainder, and forfeited his title and estate. His eldest son, however, became a zealous advocate for the Protestant succession, and supported the government during the rebellion in 1745; his grandson, Kenneth Mackenzie, was permitted to re-purchase the estate from the Crown, and was created an Irish peer, in 1 766, by the title of Baron Ardeloe, in the county of Wicklow, and Ariscount Fortrose, in Scotland, and in 1771, he was advanced to the dignity of Earl of Seaforth, which had been long enjoyed by his ancestors.
The American war commenced in 1775, and the Earl of Seaforth, in gratitude for the favors he had received, made an offer to His Majesty, to raise a regiment of foot on his estate, which, in former times, had been able to furnish a thousand men in arms. This offer was accepted in December, 1777; the Earl received a letter of service to raise a regiment of foot, of which he was appointed Lieut.- Colonel
Commandant, and in January, 1778. The establishment was to consist of fifty sergeants, two pipers, twenty drummer and fifers, and a thousand and ten rank and file.
The men were principally raised from the clan of “Caber Feidh” as the Mackenzies were called from the stag’s horns on the armorial bearings of Seaforth. Five hundred men were from the Earl of Seaforth’s own estates, and about four hundred from the estates of the Mackenzies of Scatwell, Kilcoy, Applecross, and Redcastle, all of whom had sons or brothers holding commissions in the regiment: the officers from the lowlands brought upwards of two hundred, of who seventy-four were English and Irish. The clan Macrae had long been faithful followers of the Seaforth family, and on this occasion the name was so general in the regiment, that it was frequently designated the regiment of “the Macraes.”
On the 15th of May 1778, the Earl of Seaforth’s regiment assembled at Elgin, in Moray, amounting to one thousand and forty-one rank and file; it was inspected by Major-general Robert Sken, adjutant general in North Britain, and the men were found so remarkably effective and fit for His Majesty’s service, that nearly everyone was accepted: the corps was placed on the establishment of the regular army under the designation of “Seaforth’s Highlanders;” the supernumerary men were formed into a recruiting company, and the regiment received orders to march southward, for the purpose of embarking for the East Indies. It soon afterwards obtained the numerical title of the “Seventy-Eighth Regiment."