peak in the Sidlaw Hills, about 8 miles (13 km) northeast of Perth, eastern Scotland. On the peak, with an elevation of 1,012 feet (308 metres), stand the ruins of an ancient fort traditionally identified with the castle of Shakespeare's Macbeth. Both are in close proximity to Birnam Wood, about 12 miles (19 km) to the northwest, which played a role in the traditional account of the defeat of Macbeth by Siward, earl of Northumbria, in 1054.