The Royal Scots, once known as the Royal Regiment of Foot, was the oldest and most senior infantry regiment of the line of the British Army, having been raised in 1633 during the reign of Charles I. The regiment existed continuously until 2006, when it amalgamated with the King's Own Scottish Borderers to become the Royal Scots Borderers, which merged with the Royal Highland Fusiliers, the Black Watch, the Highlanders and the Argyll and Sutherland Highlanders to form the Royal Regiment of Scotland. Wikipedia