Holyrood Abbey is a ruined abbey of the Canons Regular in Edinburgh, Scotland. The abbey was founded in 1128 by King David I. During the 15th century, the abbey guesthouse was developed into a royal residence, and after the Scottish Reformation the Palace of Holyroodhouse was expanded further. The abbey church was used as a parish church until the 17th century, and has been ruined since the 18th century. The remaining walls of the abbey lie adjacent to the palace, at the eastern end of Edinburgh's Royal Mile.