The present nave is of the thirteenth century. The chancel was built as late as 1872. The building which still abuts against the south chancel wall belongs, however, to the fifteenth century, and was a connecting hall or gallery with "the old court" of Corpus Christi College, which not only took its early name of S. Benet from the ancient church, but for some century and more possessed no other College chapel. The bells of S. Benet, we read in the old College records, were long used to call the students "to ye schooles, att such times as neede did require--as to acts, clearums, congregations, lecturs, disses, and such like." But this belongs to its story in a later age. The Pre-Conquest Church of S. Benet, as we have said, probably served a township separate and distinct from the Castle-end "borough" on the west bank of the river. After the two villages became united, the Norman Grantebrigge, and indeed the mediæval Cambridge of later days, seemed to have formed a straggling and incompact town, stretching for the most part along the Roman road which crossed the river by the bridge at the foot of Castle hill, and so eastward past S. Benet's, and onward to the open country, eventually reached Colchester across the forest uplands. This Roman Way, following the line of the modern Bridge Street, Sidney Street, S. Andrew Street, Regent Street, ran close to the eastern limit of the town, marked roughly at a later time by the King's Ditch. This was an artificial stream constructed as a defence of the town by King John in the year 1215. It was strengthened later by King Henry III., who had also intended to protect the town on this side by a wall. The wall, however, was never built, and the Ditch itself could never have been much of a defence, except, perhaps, against casual marauders, though for centuries it was a cause of insanitary trouble to the town. Branching out of the river at the King's and Bishop's Mills, just above Queen's College, it joined the river again, after encircling the town, just below the Great Bridge and above the Common now called Jesus Green. The Ditch was crossed by bridges on the lines of the principal roads. One of these, built of stone, still remains under the road now called Jesus Lane. There appears to have been a drawbridge also at the end of Sussex Street. The river itself, which formed the western boundary of the town, was spanned by two bridges, the Great Bridge at Castle End and the Small Bridge or Bridges at Newnham by the Mill pond. Between the two bridges were the principal wharfs or river hithes--corn hithe, flax hithe, garlic hithe, salt hithe, Dame Nichol's hithe. These have all now given place to the sloping lawns and gardens of the colleges, the far-famed "Cambridge Backs." The common hithe, however, below the Great Bridge still continues in use. It is with certain rights in regard to these hithes that the earliest Royal charter of which we have record deals. It is an undated writ of Henry I.