The wall of the North Aisle between the porch and the transept is divided into six compartments by Early English buttresses with gabled heads. This wall was built in Norman times, as may be seen from the small round-headed windows which light the clerestory, but was in Early English times faced with fresh ashlar, which conceals the Norman arcading of intersecting arches which ran along this wall. The triforium windows on this side are not, though they are on the south side, regularly arranged; there are none in the two western divisions, while between the easternmost buttress and the transept there are two. Six late thirteenth-century windows were cut through this wall—these are all of similar design; they consist of two lights under a comprising arch, with a circle in the head. The clerestory windows are of plainer character. Each window consists of two simple lancets set under a recessed arch without any hood moulding; the tympana also above the lancet heads are not pierced or decorated in any way; in fact, the whole clerestory is remarkably plain. Between the windows are flat buttresses. The aisles are covered with lean-to roofs of lead, the nave itself with a tiled roof of medium pitch. The gable at the east end of the nave, and indications on the east face of the tower, show that the pitch of the roof was once higher, and that it must have been lowered at some time after the tower was built in the fifteenth century.
The North Transept is most interesting. Its west wall contains two round-headed windows with billet moulding, the northern one blocked up; and at the north-west corner is a cluster of cylindrical shafts running up to about the same height as the walls of the aisle. Why they terminated here it is hard to say; they may mark the termination of the original Norman wall. This wall may not have risen above this height, or the upper part may have been taken down and rebuilt when the large Perpendicular window was inserted in the north end of the transept. At the north-east corner of the transept stands a richly-ornamented turret of Norman date. Round the lower part of this the arcade of intersecting arches which runs round the whole transept is carried; above this, round the turret, runs an arcading of semicircular-headed arches springing from pairs of shafts; above this the wall is decorated with diaper work; and finally, another arcading, this time of round-headed arches rising from single shafts, encircles the turret. The turret is capped by a sloping roof of stone attached to the transept wall. This turret is worthy of close attention, because it shows how the Norman builders hated monotony; each stage has its own decoration unlike that of any other; and, moreover, there are variations in the shafts of the arcading—some are plain, [!--IMG--]
To the east of the transept may be seen the Choir and Presbytery, with its four clerestory windows; the Choir Aisle, also with four windows; the Lady Chapel, with the octagonal turret-staircase leading into Saint Michael's Loft above it. It will be noticed that there is no window in the aisle under the western clerestory window of the choir, as the space where this would have been found is occupied by the two chapels to the east of the transept, and also that the aisle extends beyond the choir and flanks the western part of the Lady Chapel. The whole of this part of the church is of Perpendicular character. The windows of the choir aisles are low, the arches are depressed, and the curvature of each side of the arch is so slight that they appear almost straight lines. The body of these windows contains four lights; in the head, each of these is subdivided into two. Between the aisle windows are buttresses, which, with the exception of the one opposite the east wall of the choir, which terminates in a gable, have pinnacled cappings; and from each of these, save the gabled one, a flying buttress is carried over the roof of the aisle and rests against the choir wall. The aisle roof is flat, and at the top of the outer wall runs a plain parapet pierced with quatrefoil openings. The clerestory windows are of great size and are set close together. The choir roof is flat and is quite invisible from the exterior. There can be little doubt that a parapet at one time ran along the tops of the clerestory walls, but this has disappeared. The Lady Chapel has on either side three large Perpendicular windows; the arches of these as well as those of the clerestory have pointed heads. The western half of the central window of the Lady Chapel is blocked up by the later-built octagonal [!--IMG--]
The buttresses at the east angles of the Lady Chapel are set diagonally, and rise in five stages; the upper stage of each is square, in section, with the faces parallel to the walls of the church, and reaches a higher level than the parapet, and is finished with a flat cap. The large east window is a Perpendicular one of five lights. From the base of the south-east buttress runs a wall dividing the burying-ground from the gardens of the house, to the south of the church, which stands on the site of the domestic buildings of the priory. The portion of the wall of the Lady Chapel beneath the easternmost window on the north side is modern. Here Mr Ferrey, the architect, by whom much of the restoration was carried out, discovered traces of an external chantry and the marks of an arcading corresponding to that still remaining on the inside.
The object of the chamber above the Lady Chapel is uncertain,—in 1617 it is described as "St Michael's Loft," in 1666 the parishioners described it as "heretofore a chapter-house," when petitioning the bishop to allow it to be used as a school. But if it was ever used as a chapter-house, it could only have been for a short time, as there is evidence that there was a chapter-house to the south side of the choir in the twelfth century, and that this remained as late as 1498. The south side of the Lady Chapel and choir correspond very closely with the north side, but there are several differences to be noticed between the south and north transepts. On the eastern side of the South Transept the Norman apsidal chapel still remains. This has a semi-conical roof with chevron table moulding under it, and two windows—one of original Norman work, the other a three-light Early English window. A sacristy of Early English date stands to the east of the apsidal chapel, and occupies the space between the apse and the south choir wall. At the south-east corner of the transept there is a circular stair turret corresponding to some extent with the turret at the north-east angle of the north transept; this, in the second stage, becomes octagonal in section, and rises above the parapet of the transept. In the south face is a depressed segmental window, much smaller than the corresponding window on the north side, under a gabled parapet. The pitch of the roof of the south transept is much higher than that of the north transept, and the upper part of the transept does not abut against the walls of the church. Two tiers of corbel brackets on the south wall, and traces of two Norman windows seem to indicate that here, as elsewhere, a slype, with a room above it, intervened between the south end of the transept and the chapter-house. This slype was generally a passage connecting the cloister garth with the smaller garth to the south of the choir which was often used as a burying-place for the abbots or priors, as the case may be, and was the place where the monks or canons interviewed visitors and chapmen. The room above was often used as the library. The south of the Nave is decidedly inferior in interest to the north. The cloisters have entirely disappeared, but a series of round-headed arches, formed of stucco, may conceal a stone arcading similar to that hidden by the Early English facing of the north wall. The small round-headed windows giving light to the triforium are more regularly arranged than on the north side; there is one, and only one, in each division between the buttresses. There were, as usual, two doors in this wall: one for the canons, in the wall opposite to the west of the cloister, one close to the transept for the prior; both are now blocked up. The prior's door, in the injunction of Langton, 1498, is directed to be kept locked, save when on festivals a procession passed through it. This doorway is of early thirteenth-century work; it is round-headed, and is French in character. There is a legend that a party of French monks, terrified by a dragon which rose out of the sea, possibly an ancestor of the sea-serpent of more modern days, put in to Christchurch haven, and were entertained by the canons, with whom they abode for many years; possibly this door may be of their workmanship or design. In the south wall a large aumbry or cupboard, in the thickness of the walls, may be seen; in this possibly the canons kept the books that they had brought from the library for study. What the windows in this aisle were we cannot say—originally, no doubt, Norman, for the westernmost window is still of this style; but the others, which were widened either in Early English or Decorated times, are now all filled with nineteenth-century tracery of Decorated type. The buttresses between the windows, unlike those on the north side, are flat Norman ones. Towards the west end of the aisle a passage has in modern times been cut through the wall, and when this was done remains of a staircase which, no doubt, led to the dormitory, were discovered. The clerestory, on this side, is of the same plain character as on the north side.