there was probably only sufficient time to strengthen
the earthworks and to build stockades, but soon afterwards William
erected a permanent castle of stone on this marsh frontier--a building
Fuller describes as a "stately structure anciently the ornament of
Cambridge." In her scholarly work on the town, Miss Tuker tells us how
Edward III. quarried the castle to build King's Hall; how Henry VI.
allowed more stone to be taken for King's College Chapel; and how Mary
in 1557 completed the wiping out of the Norman fortress by granting to
Sir Robert Huddleston permission to carry away the remaining stone to
build himself a house at Sawston! Wherever building materials are
scarce such things have happened, even to the extent of utilizing the
stones of stately ruins for road-making purposes. It thus comes about
that the artificial mound and the earthworks on the north side of it
are as bare and grass-grown as any pre-historic fort which has not at
any period known a permanent edifice.

Owing to its fairs, and particularly to the famous Stourbridge Fair,
an annual mart of very great if uncertain antiquity, held near the
town during September, Cambridge at an early date became a centre of
commerce, and it had risen to be a fairly large town of some
importance before the Conquest. In the time of Ethelred a royal mint
had been established there, and it appears to have recovered rapidly
after its destruction by Robert Curthose in 1088, for it continued to
be a mint under the Plantagenets, and even as late as Henry VI. money
was coined in the town.

A bridge, as already stated, was built at Cambridge in the ninth
century, but in 870, and again in 1010, the Danes sacked the town, and
it would seem that the bridge was destroyed, for early in the twelfth
century we find a reference to the ferry being definitely fixed at
Cambridge, and that before that time it had been "a vagrant,"
passengers crossing anywhere that seemed most convenient. This fixing
of the ferry, and various favours bestowed by Henry I., resulted in an
immediate growth of prosperity, and the change was recognized by
certain Jews who took up their quarters in the town and were, it is
interesting to hear, of such "civil carriage" that they incurred
little of the spite and hatred so universally prevalent against them
in the Middle Ages. The trade guilds of Cambridge were founded before
the Conquest, and, becoming in course of time possessed of wealth and
influence, some