Edinburgh Castle was originally a 6th century fortification, mentioned in an old Welsh poem the Gododdin of Aneurinan. Standing on a high volcanic plug, there are extremely steep slopes to the north, south and west, only the east side gives a manageable approach. In the late 11th century, the Citadel was held by Malcolm Canmore and his consort Margaret and it was her son King David I who founded the royal stone enclosure fortress. In the 12th century, he probably added to the summit of Castle Rock, St Margaret's Chapel which was used as a 'Gunner's Storehouse' after the Reformation. Around 1370, David's Tower was added as the royal residence in the castle, originally a high L-plan tower house, its re-entrant angle was later fill to make it square in plan. In 1573 during the Lang Siege, an artillery bombardment by English troops, brought down the south wall of David's Tower and the Regent Morton added the Half-Moon Battery over its vaulted chambers. At various times in its history, the castle was besieged or defended by the forces of Scotland, France and England and sadly its medieval fortifications were destroyed. The few significant buildings that remain, are St Margaret's Chapel, the early 16th century Great Hall and the Royal Palace, which contains the Honours of Scotland and the Stone of Destiny. A mile east is the Palace of Holyroodhouse and 4 miles north-west is Lauriston Castle.