This gatehouse is generally attributed to Edward III., who may have constructed it in the later part of his reign; or it may be the work of Richard II. The vaulting and portcullis-arch appear of later date than the walls, but the whole is probably of the transition period between Decorated and Perpendicular. In the survey of Henry VIII. this is called the Garden Tower, being close to the constable’s garden, now the parade. In the survey of 1597, it is called by its present name; and popular prejudice, rather than Tower tradition, has attributed that name to the murder of the sons of Edward IV., idly said to have been perpetrated here. [Illustration: BELL TOWER.—BASEMENT.] As Garden Tower, this building was a well-known Tudor prison. From hence to Bell Tower, 150 feet, the original curtain remains, of its full height of about 40 feet, and its base thickness about 10 feet. It is, however, so defaced outside, and inside so encrusted with houses of the Tudor period, that but little of its detail can be seen. It is pretty clear that there is no range of loopholes in its substance. A cell, recently a stable, is really a Tudor brick vault built against it. Near to Bell Tower is an original mural chamber, probably a garderobe, lighted by a recess and loop. This recess shows the original wall, about 7 feet thick; and an interior addition of 3 feet more. The original recess has an acute, and the addition a drop arch. The one may be early English, and the other of Decorated date. Above this the full thickness of the wall is seen in the great modern window, cut through it, in the constable’s lodging. Bell Tower is so called from the alarm bell once suspended from its summit. The bell now discharges the less exciting duty of summoning the garrison to St. Peter’s Church, and the bell turret has been replaced by a _gazebo_. The tower caps the south-west angle of the ward, and stands 40 feet within the Byward Gate, which it commands. It is in plan an irregular octagon, about 35 feet mean diameter, and 60 feet high, from the level of the outer ward. Five and a half of its sides project beyond the curtains. Above, the angles are rudely rounded off, and the upper 20 feet is cylindrical, and may be an early addition. The two southern faces have a chamfered plinth, 6 feet high. The walls have been stuck over with chips of flint, and the parapet is a brick addition; but it is evident that the basement was originally of fine jointed ashlar, almost equal to Wakefield. Five cruciform loops mark the line of the interior basement, about 14 feet above the exterior ground. [Illustration: BELL TOWER.—FIRST FLOOR.]