ROMANO-BRITISH LONDON found in peaty soil which had never received a covering of tidal mud, and in the Deverell Street cemetery the ancient level was 2 J ft. Ordnance datum. The military road would have passed mainly over gravel between Deptford and Stanegate, but even the alluvium bordering the river was inhabited, the houses generally resting on piles. Isolated houses existed along the main roads outside London but the population was mainly concentrated on the north bank in that part of the triangle formed by the roads which was not given up to burials ; while on the opposite side of the river even the flats now below high- water mark were occupied by houses built on piles, and the main roads flanked by dwellings here and there. That the two banks were joined by a bridge to carry the Ermine Street is more than probable when it is remembered that the Tyne was spanned by a Roman bridge of stone, and that Julius Caesar bridged the Rhine in ten days, at a point where the stream is considerably wider than the Thames at London Bridge. Further, mention is made of London Bridge in the reign of Edgar, and the Roman army is much more likely even than King Alfred to have accomplished the work in the first instance. At the end of the third century a prosperous community on a tidal river accessible from the Channel could hardly hope for permanent immunity from the pirates who then made their appearance, and a wall along the river front seems a necessary feature of the scheme of defence eventually adopted. This in itself argued a weakening of the imperial power, and a general deterioration seems to have set in before long. The City wall reduced to a minimum the flow of the Walbrook, and created a swamp outside that remained undrained and uninhabited for centuries. Nothing definite is known of London's fate at the hands of Teutonic invaders when the protection of Rome was withdrawn about 410 ; but as will be seen in the sequel, there is no reason to suppose that the City was occupied, even if it was captured, by the Anglo-Saxons of the pagan period. In the general insecurity of the fifth and six centuries trade must have languished and population dwindled ; but there is little hope of lifting the veil that now descends on Londinium. The Roman City Wall of London^ The most definite survival of Roman London is the wall with which the City was ultimately surrounded. Its line along the land side is clearly to be traced from the Tower northwards to Aldgate, thence to Bishopsgate, following the street called London Wall to Cripplegate, where it turns to the south until just east of Aldersgate, and again taking a westerly course it passes through the site of Christ's Hospital to Newgate, and southwards to Ludgate. Its further course to the Thames is less certain, and along the south side or river front it is altogether doubtful. With slight modifications the Roman boundary continued to be that of the inclosed portion of London throughout the subsequent periods during ' The references in red on Plan C showing the site of the Roman wall are indicated in the text by italic numbers. 43
