adually
extended eastward by Abbots Roger of Norton and John of Berkhampstead;
first the Saint's Chapel was built, then the retro-choir, and finally
the Lady Chapel, which was finished by Abbot Hugh of Eversden in 1326.

Another change was necessitated by an event which took place on St.
Paulinus' Day, October 10th, of the year 1323. For on that day a
calamity such as had never before happened befell the church. The
celebration of Mass at an altar of the Blessed Virgin was just over, a
great multitude of people, men and women, still being in the church,
when two of the Norman piers of the main arcade on the south side fell
outwards one after the other with a great crash, and about the space of
an hour afterwards the wooden roof of the nave which had been supported
by these columns also fell; the piers themselves had crushed the south
wall of the aisle and the cloisters, so that a complete wreck was made
of the south-eastern part of the church westward of the tower. But this
disaster was accompanied by a great marvel, for though many persons were
standing close by, not one was injured; and a still more wonderful thing
is recorded: the monk whose duty it was to guard the shrine of St.
Amphibalus, which at that time stood in the nave, had been celebrating
at the altar--he had finished even to the washing of the sacred
vessels--when he saw the columns fall; he withdrew a little from the
altar and received no harm. Some of the wreckage fell on the shrine of
St. Amphibalus, and though the marble pillars supporting the canopy were
broken, yet the chest which contained his relics suffered no harm. This
wonderful preservation of life and limb and shrine was naturally
attributed to the intervention of the blessed martyr St. Amphibalus.

Abbot Hugh of Eversden began to rebuild this ruined part of the church,
and this accounts for the five bays of the nave arcading westward of the
rood-screen being in fourteenth-century style. He did not live to finish
all this work, but it was carried on by his successor, Richard of
Wallingford (1326-1335), and finished by the next Abbot, Michael of
Mentmore, about 1345. The present rood-screen, which probably took the
place of a previously existing one of Norman date, was built in 1360 by
Thomas de la Mare. No further change of importance was made until the
time of John of Wheathampstead, who was Abbot from 1420 to 1440, and
again from 1451 to 1464. He left his marks in various parts of the
Abbe