Erskine became an equerry or master of the stable to Mary, Queen of Scots, first serving her as a cup bearer or éschanson in France.
John Knox noted that he accompanied her during her formal Entry to Edinburgh in September 1561.
[5] Erskine was a guest at Mary's supper at Holyrood Palace on 9 March 1566 when David Rizzio was murdered.
[11] Anthony Standen, who served as Darnley's equerry, wrote that Mary was mounted behind Erskine, Darnley was on another horse, and there were six in the party riding to Dunbar, including the Laird of Traquair, and a chamberer or servant for Mary.
[13] As one of the masters of the queen's stable, Erskine kept an account with Robert Abercromby, an Edinburgh craftsman who made saddles and reins.