With the exception of the chapel, its crypt, and sub-crypt, which were vaulted throughout, all the floors were originally of wood, and were supported on double rows of stout oak posts, which in their turn sustained the massive oak main floor beams.
The forebuilding, on the south face of the keep, was probably added by Henry II. It survived until 1666, as it is shown in a view of the Tower executed by Hollar about that date; but it appears to have been removed prior to 1681.
The chapel of St. John is a fine example of early Norman ecclesiastical architecture. It consists of a nave, with vaulted aisles, having an apsidal eastern termination. It is covered by a plain barrel vault, and on the fourth floor level has a triforial gallery, also vaulted. It is connected by two doors with the gallery in the thickness of the wall that surrounds this floor, from one of the windows of which it is said that Bishop Ralph Flambard effected his remarkable escape.
It is probable that at first (except the chapel, which was covered by its own independent roof) there were two separate high-pitched roofs, one covering each division, and not rising above the battlements, the wall gallery serving as a kind of additional fighting deck, for which reason it was carried round the triforium of the chapel. As the need for this diminished, two large additional rooms were gained by raising the central wall a story, and superposing a flat, lead roof.
The absence of privacy, fireplaces, and sanitary accommodation on this fourth floor, with the cold draughts from the stairways and windows of the wall-gallery, must have been well-nigh intolerable; nor could wooden screens, hangings, or charcoal brasiers have rendered it endurable. It is not surprising, therefore, that under Henry III. the palace was considerably enlarged, or that these chambers were abandoned by him for warmer quarters below, in the Lanthorn Tower "k," and its new turret "J" although the chapel and council chamber continued to be used down to a much later date.
After the siege of Rochester by William Rufus in 1088, Gundulf had built a stone wall round the new castle of Rochester. This probably moved the King to enclose the Tower of London with a similar wall, for the Saxon Chronicle tells us that in 1091 "a stone wall was being wrought about the Tower, a stone bridge across the Thames was being built, and a great hall was being erected at Westminster, whereby the citizens of London were grievously oppressed."[14]
Now, as Gundulf did not die until 1108, it is by no means improbable that, while superintending the erection of these two great towers at London and Colchester,[15] he also constructed the stone wall round the former, for the chronicler says of him that "in opere cæmentarii plurimum sciens et efficax erat."[16]
As it is on record that the smaller keep of Dover, built by Henry II. nearly a century later, was upwards of ten years in construction, while some additional time had been consumed—in the collection of materials and workmen—with the preliminary preparation of the site, it does not seem probable that the great Tower of London (honeycombed as its walls are with cells and mural passages) could have been erected in a much shorter space of time. When the ruder appliances of the earlier period are taken into account, such a keep could not have been built in a hurry, for time would be needed to allow the great mass of the foundation to gradually settle, and for the mortar to set. Although preparations for its erection may have begun as early as 1083, it seems more probable that the White Tower was not commenced much before 1087, or completed before 1097.
Stow, quoting from FitzStephen's Description of London,[17] mentions the White Tower as being "sore shaken by a great tempest of wind in the year 1091," which, as I do not (with the conspicuous modesty of the late Professor Freeman) "venture to set aside the authority of the chronicles"[18] when they have the audacity to differ from my preconceived ideas, seems to me reasonable ground upon which to argue that not only was the White Tower then in course of erection, but that in that year the works were not in a very advanced state. That it must have been completed prior to 1100 is evidenced by the fact that King Henry I., on succeeding to the throne in August of that year, committed to the custody of William de Mandeville, then Constable of the Tower, his brother's corrupt minister, Ranulph (or Ralph) Flambard, Bishop of Durham. The chronicler exultingly tells us that he was ordered[19] "to be kept in fetters, and in the gloom of a dungeon," which must have been either "Little Ease" or the small dark cell opening from the crypt of St. John's Chapel, afterwards rendered famous by the imprisonment there of Sir Walter Raleigh.