Edinburgh Castle is a historic castle in Edinburgh, Scotland. It stands on Castle Rock, which has been occupied by humans since at least the Iron Age. There has been a royal castle on the rock since at least the reign of Malcolm III in the 11th century, and the castle continued to be a royal residence until 1633. From the 15th century, the castle's residential role declined, and by the 17th century it was principally used as a military garrison.