with a gun loop which overlooked High Street: a recess was made in the outer battery wall to reveal this gun loop. In 1912–1913 the adjacent Fore Well was cleared and surveyed and was found to be deep, mostly hewn through the rock below the castle. Crown Square Crown Square, also known as Palace Yard, was laid out in the 15th century, during the reign of King James III, as the principal courtyard of the castle. The foundations were formed by the construction of a series of large stone vaults built onto the uneven Castle Rock in the 1430s. These vaults were used as a state prison until the 19th century, although more important prisoners were held in the main parts of the castle. The square is formed by the Royal Palace to the east, the Great Hall to the south, the Queen Anne Building to the west, and the National War Memorial to the north. Royal Palace The Royal Palace comprises the former royal apartments, which were the residence of the later Stewart monarchs. It was begun in the mid 15th century, during the reign of James IV, and it originally communicated with David's Tower. The building was extensively remodelled for the visit of James VI to the castle in 1617, when state apartments for the King and Queen were built. On the ground floor is the Laich (low) Hall, now called the King's Dining Room, and a small room, known as the Birth Chamber or Mary Room, where James VI was born to Mary, Queen of Scots, in June 1566. The commemorative painted ceiling and other decorations were added in 1617. On the first floor is the vaulted Crown Room, built in 1615 to house the Honours of Scotland: the crown, the sceptre and the sword of state. The Stone of Scone, upon which the monarchs of Scotland were traditionally crowned, has been kept in the Crown Room since its return to Scotland in 1996. To the south of the palace is the Register House, built in the 1540s to accommodate state archives. Great Hall The Great Hall measures , and was the chief place of state assembly in the castle, although there is no evidence that the Parliament of Scotland ever met here, as is sometimes reported. Historians have disagreed over its dating, although it is usually ascribed to the reign of King James IV, and is