'Alexander Lasley Generall of the Scottish Army', 1642

Engraving, published by John Stafford, 1642.

Equestrian portrait of Alexander Leslie, 1st Earl of Leven (1580 (c)-1661).

Leslie had served for thirty years in the army of the Swedish King, Gustavus Adolphus. He was probably the most experienced officer who fought in the Civil War.

Leslie organized and commanded the Scottish armies which fought in the Bishops' Wars of 1639-1640. In 1644 he led the army of 20,000 foot and 2,000 horse which the Scots raised in support of Parliament. In July that year, in one of the decisive battles of the war, the combined Scottish and Parliamentarian armies defeated the Royalists, commanded by Prince Rupert, at Marston Moor. In the following October, Leslie's forces captured the Royalist stronghold of Newcastle.

Charles I surrendered to the Scots in May 1646, and was placed in Leslie's charge at Newcastle, where he remained until he was handed over to Parliament the following year.