Archibald Strachan (died 1652) was a Scottish soldier who fought in the Wars of the Three Kingdoms, reaching the rank of colonel.
Early in the English Civil War Strachan served in the English Army under Sir William Waller taking part in a number of actions, before being assigned to garrison duty. He later joined the Scottish Army as a major in Sir John Brown's regiment of horse and fought at the battle of Battle of Annan Moor in October 1645. In 1648 he rejoined the English army and served with the rank of major under Cromwell at the Battle of Preston (1648). With the execution of Charles I, the political situation in Scotland was unstable. Strachan supported the anti-royalist faction and took command of the Scottish Parliamentary army which defeated Royalist general Montrose at the Battle of Carbisdale. However the Scottish Parliament and a section of the Kirk party forged an alliance with Charles, Prince of Wales, offering him the crown of Scotland.
The Scottish Parliament made Strachan a commander of Scottish forces in the west, but Strachan joined the faction of the Kirk party which signed the Western Remonstrance. This faction demanded that the Act of Classes (1649) was enforced (removing Engagers from the army and other influential positions) and remonstrating against Charles being crowned King of Scotland. Strachan eventually defected to Cromwell.[1][2] [3] For his perceived act of betrayal he was excommunicated by the Kirk in January 1651 and in April the same year declared a traitor suffering the forfeiture of his property. He died the next year due to his grief from his excommunication.[4]