 His father, Patrick Douglas of Standingstone (d.1626), was a son of William Douglas of Whittinghame (d.1595) by his spouse Elizabeth, daughter of Sir Richard Maitland of Lethington, Knt.Many Scottish soldiers, infantry and cavalry, found themselves engaged in the various wars that are collectively called the Thirty Years' War and Robert Douglas was one of these.In 1627 he was received as a page in the Swedish service under John Casimir, Count Palatine of Kleeburg, castellan of Stegeborg Castle, brother-in-law of King Gustav II Adolf.