The force which the Robertsons could bring into the field was estimated at 800 in 1715, and 700 in 1745.
Of the branches of the family, the Robertsons of Lude, in Blair-Athole, are the oldest, being of contemporary antiquity to that of Strowan.
Patrick de Atholia, eldest son of the second marriage of Duncan de Atholia, received from his father, at his death, about 1358, the lands of Lude. He is mentioned in 1391, by Wyntoun (Book ii. p. 367) as one of the chieftains and leaders of the clan. He had, with a daughter, married to Donald, son of Farquhar, ancestor of the Farquharsons of Invercauld, two sons, Donald and Alexander. The latter, known by the name of Rua or Red, from the colour of his hair, acquired the estate of Straloch, for which he had a charter from James II. in 1451, and was ancestor of the Robertsons of Straloch, Perthshire. His descendants were called the Barons Rua. The last of the Barons Rua, or Red, was Alexander Robertson of Straloch, who died about the end of the last century, leaving an only son, John, who adopted the old family soubriquet, and called himself Reid (probably hoping to be recognised as the chief of the Reids). John Reid entered the army, where he rose to the rank of General, and died in 1803, leaving the reversion of his fortune (amounting to about £70,000) for the endowment of a chair of music, and other purposes, in the University of Edinburgh. This ancient family is represented by Sir Archibald Ava Campbell, Bart.
Donald, the elder son, succeeded his father. He resigned his lands of Lude into the king’s hand on February 7, 1447, but died before he could receive his infeftment. He had two sons: John, who got the charter under the great seal, dated March 31, 1448, erecting the lands of Lude into a barony, proceeding on his father’s resignation; and Donald, who got as his patrimony the lands of Strathgarry. This branch of Lude ended in an heiress, who married an illegitimate son of Stewart of Invermeath. About 1700, Strathgarry was sold to another family of the name of Stewart.
The Robertsons of Inshes, Inverness-shire, are descended from Duncan, second son of Duncan de Atholia, dominus de Ranagh, above mentioned.
The Robertsons of Kindeace descend from William Robertson, third son of John, ancestor of the Robertsons of the Inshes, by his wife, a daughter of Fearn of Pitcullen. He obtained from his father, in patrimony, several lands about Inverness, and having acquired great riches as a merchant, purchased, in 1615, the lands of Orkney, Nairnshire, and in 1639, those of Kindeace, Ross-shire; the latter becoming the chief title of the family.
The Robertsons of Kinlochmoidart, Inverness-shire, are descended from John Robertson of Muirton, Elginshire, second son of Alexander Robertson of Strowan, by his wife, Lady Elizabeth, daughter of the Earl of Athole.
The fifth in succession, the Rev. William Robertson, one of the ministers of Edinburgh, was father of Principal Robertson, and of Mary, who married the Rev. James Syme, and had an only child, Eleonora, mother of Henry, Lord Brougham. The Principal had three sons and two daughters.