“It is probable, however, that, at a very early period after its erection, towers were reared upon London Bridge, for there was one standing at each end; but of these I shall speak more largely under future years: remarking only, that it is by no means impossible for a Watch-tower and gate to have stood upon the Bridge, even from its very first erection, seeing that it was, as it were, a new key to the City. A sort of Barbican, Mr. Geoffrey, such as you derive your name from; for you remember the essential importance which such buildings were of, and how Bagford speaks of them in his Letter to Hearne, which I have already quoted, page lxii. ‘Here,’ says he, ‘they kept Cohorts of Souldiers in continual service’--for your Barbican Tower was of Roman invention,--‘to watch in the night; that if any sudden fire should happen, they might be in a readiness to extinguish it, as also to give notice if an enemy were gathering or marching towards the City to surprise them. In short, it was a Watch-tower by day; and at night, they lighted some combustible material on the top thereof, to give directions to the weary traveller repairing to the City, either with provision or on some other occasion.’ “But to pass from probabilities to certainties, let us now, having got the Bridge fairly built of stone, consider the many events and changes which it hath experienced, from its infancy in the thirteenth Century, to its old age in the nineteenth: and so, my excellent auditor, Here begin the Books of the Chronicles of London Bridge.