In the time of Juliana, who probably succeeded Mary, and was certainly abbess for about thirty years before her death in 1199, the transitional work in the clerestory of the nave was carried out.
In the next century the church was extended westward by the erection of three bays and the west front with its three tall lancets and the small cinquefoil window above the central one, all inclosed within a pointed comprising arch. This work was done during the time when Henry III was king; there are records of several gifts to the abbey of timber by him from the royal forest. This was no doubt used in constructing the roof of the westward extension of the nave and aisles. The next work was the insertion of the two large east windows and the building of the pair of Decorated chapels, one of which was dedicated to Our Lady, and the other to St. Æthelflæd, or Ethelfleda, as her name was then spelt. They were probably divided by an arcade, and stood until the dissolution of the Abbey, when they were pulled down, being of no further use in the church of the abbey which was purchased by the people of Romsey and converted into a parish church.
It has been said that little Perpendicular work is to be seen in Romsey Abbey, but some did exist at one time. At Romsey, as at Sherborne, there were disputes between the abbey and the town, though fortunately at Romsey an amicable arrangement was arrived at. The north aisle of the abbey church had been for many years set apart for the use of the people of Romsey as a parish church, and was known by the name of St. Laurence; in the year 1333 the abbess endowed a vicarage. As the town increased in size the north aisle became too strait for the parishioners, and at times of great festivals they used to encroach on the nuns’ church. This led to disputes, and the matter was referred to William of Wykeham, the celebrated Bishop of Winchester, remodeller of his cathedral church, and founder of Winchester School, and New College, Oxford. He persuaded the nuns to give up the north arm of the crossing to make a choir for a new parish church to be built adjoining the abbey church, in such a way that the north aisle should be cut off by a wall and included in the new church. The north aisle of the abbey church thus became the south aisle of the parish church, the new building its nave, and the north end of the transept of the abbey church the parish chancel, the Norman apsidal chantry attached to the transept made a fitting eastern termination to the chancel. A chantry of the Confraternity of St. George, built on the north side of the new church, took the place of a north aisle. This was separated from the nave by a carved oak screen, part of which has been utilized in the construction of the screen between the nave and choir of the existing church. The building of this new parish church unfortunately involved the destruction of the north porch of the abbey church. When, after the dissolution of the nunnery, the people bought the abbey church of the King, the nave and north aisle of the new parish church were no longer needed, and were therefore demolished, the windows were inserted in the arches that had been cut in the wall of the north aisle of the abbey church, when these openings were again walled up. Two of these have, however, been removed, and modern Norman windows constructed on the old mouldings have taken their place. A doorway which had been cut in the north wall of the transept when the new parish church was built was no longer used after the church was pulled down, and a low side window near it has been blocked up and converted into a cupboard. The two eastern chapels were also demolished, and their east windows were inserted in the masonry used to block up the entrances into the chapels from the ambulatory. During the time that succeeded the Reformation many changes were made in the fittings of the church, galleries were erected in the transept and at the west end of the nave where the organ was placed. The walls were covered with whitewash, and probably with a view to make it easier to warm the church, walls were built behind the triforium arcading all round the church. These walls are shown in some of the illustrations made a few years ago; they have now been entirely removed. The internal appearance of the church about the middle of the nineteenth century was extremely distasteful to those affected by the Gothic revival, and drastic changes were made. “Restoration” was begun at first under the direction of Mr. Ferrey, who also restored Christchurch Priory. The inner roof of the three western bays of the nave aisles which had not been, like those of the other bays, vaulted in stone, were restored in wood and plaster about 1850, when the Hon. Gerard Noel was vicar; the nave roof was rebuilt a little later. Under the direction of Mr. Christian, architect to the Ecclesiastical Commissioners, the chancel roof was restored, and the roof of the north arm of the transept was taken in hand by Mr. Berthon. Other work has been done more recently, and the present vicar has the intention of building a porch with a room over it on the north side, to take the place of the porch which was destroyed when the nave of the church of St. Laurence was built in the time of William of Wykeham, as already described.
The curious wooden erection on the top of the tower, somewhat resembling a hen coop or gigantic lobster pot, was added in comparatively recent times to contain the bells; drawings made at the beginning of the nineteenth century do not show it, but, those made about the middle of the century do. It is ugly, and adds nothing to the dignity of the church; probably the tower was originally crowned by a pyramidal roof which gave it the appearance of height so much required.
The east ends of the two choir aisles have in quite recent years been provided with altars and fitted up as chapels for week-day services. The two apsidal chapels attached to the transept are used as vestries, the one on the south for clergy and that on the north for the choir.