John Erskine, 22nd and de jure 6th Earl of Mar, KT (1675 - May 1732), Scottish Jacobite, was the eldest son of the 21st Earl of Mar (who died in 1689), from whom he inherited estates that were heavily loaded with debt. By modern reckoning he was 22nd Earl of Mar of the first creation (from c. 1114) and de jure 6th Earl of Mar of the seventh creation (from 1565). He is sometimes also termed the 11th Earl of Mar in the Scottish Peerage, which was reckoned from the second creation (from 1426). He was nicknamed "Bobbing John" for his tendency to shift back and forth from faction to faction, whether from Tory to Whig or Hanoveran to Jacobite.
Meeting many Highland chieftains at Aboyne, he avowed an earnest desire for the independence of Scotland and, at Braemar on 6 September 1715, he proclaimed James VIII King of Scotland, England, France and Ireland, thus beginning the '15 Jacobite rising. Gradually the forces under his command were augmented, but as a general he was a complete failure. Precious time was wasted at Perth, a feigned attack on Stirling was resultless, and he could give little assistance to the English Jacobites. At Sheriffmuir, where a battle was fought in November 1715, Mar's forces largely outnumbered those of his opponent, the Duke of Argyll; but no bravery could atone for the signal incompetence displayed by Lord Mar, and the fight was virtually a decisive defeat for the Jacobites.
Mar then met James Edward at Fetteresso; the cause however was lost, and Mar and the Prince fled to France, where he would spend the remainder of his life. The Hanoveran court passed a Writ of Attainder for treason against Mar in 1716 as punishment for his disloyalty; this was not lifted until 1824.
Mar sought to interest foreign powers in the cause of the Stuarts; but in the course of time he became thoroughly distrusted by the Jacobites. In 1721 he accepted a pension of £3500 a year from George I, and in the following year his name was freely mentioned in connection with the trial of Bishop Atterbury, whom it was asserted that Mar had betrayed. This charge may perhaps be summarised as not proven. At the best his conduct was highly imprudent, and so in 1724 the Young Pretender finally broke with Mar. His later years were spent in Paris and at Aix-la-Chapelle, where he died in 1732.