James Boswell's uncle John was a member of a sect known as the Glasites.
Henry ErskineDied Aug 09, 1765
Son of John Erskine (d. 1739), 3rd of Alva, and Catherine Sinclair. Married (1761) to Janet Wedderburn (or Wederburn), a sister of Alexander Wedderburn, 1st Earl of Rosslyn. John Erskine was a distant cousin of Andrew Erskine, and also - and slightly less distant - of James Boswell himself.
In 1747 he inherited the Baronetcy of Alva from his older brother Charles Erskine, who was killed at the battle of Val on July 2, 1747. In 1749 he was elected MP for Ayr, and from 1754 until his death for Anstruther. At the time of his death he was even a Lt-Gen in the army, as well as Secretary to the Order of the Thistle.
Boswell describes him as "[a]n intimate friend of Lord Bute" [PM in 1762-3] in The Life of Samuel Johnson, LL.D..