F. 7.—­But this time it was with legions and not with cohorts that the enemy had to do.  Their first desperate charge spent itself before doing any serious damage to the masses of disciplined valour confronting them, and the Romans, once in formation, were able to deliver a counter-charge which proved quite irresistible.  On every side the Britons broke and fled; the main stream of fugitives unwisely keeping together, so that the pursuers, cavalry and infantry alike, were able to press the pursuit vigorously.  No chance was given for a rally; amid the confusion the chariot-crews could not even spring to earth as usual; and the slaughter was such as to daunt the stoutest patriot.  The spell of Caswallon’s luck was broken, and his auxiliaries from other clans with one accord deserted him and dispersed homewards.  Never again throughout all history did the Britons gather a national levy against Rome.

F. 8.—­This break-up of the patriot confederacy seems, however, to have been not merely the spontaneous disintegration of a routed army, but a deliberately adopted resolution of the chiefs.  Caesar speaks of “their counsel.”  And this brings us to an interesting consideration.  Where did they take this counsel, and why did the fleeing hosts follow one line of flight?  And how was the line of the Roman advance so accurately calculated upon by Caswallon that he was able to place his “stations” along it beforehand?  The answer is that there was an obvious objective for which the Romans would be sure to make; indeed there was almost certainly an obvious track along which they would be sure to march.  There is every reason to believe that most of the later Roman roads were originally British trackways, broad green ribands of turf winding through the land (such as the Icknield Way is still in many parts of its course), and following the lines most convenient for trade.

F. 9.—­But, if this is so, then that convergence of these lines on London, which is as marked a feature of the map of Roman Britain as it is of our railway maps now, must have already been noticeable.  And the only possible reason for this must be found in the fact that already London was a noted passage over the Thames.  That an island in mid-stream was the original raison d’etre of London Bridge is apparent from the mass of buildings which is shown in every ancient picture of that structure clustering between the two central spans.  This island must have been a very striking feature in primaeval days, coming, as it did, miles below any other eyot on the river, and must always have suggested and furnished a comparatively easy crossing-place.  Possibly even a bridge of some sort may have existed in 54 B.C.; anyhow this crossing would have been alike the objective of the invading, and the point d’appui of the defending army.  And the line both of the Roman advance and of the British retreat would be along the track afterwards known as the Kentish Watling Street.  For here again the late British legends which tell us of councils of war held in London against Caesar, and fatal resolutions adopted there, with every detail of proposer and discussion, are probably founded, with gross exaggeration, upon a real kernel of historic truth.  It was actually on London that the Britons retired, and from London that the gathering of the clans broke up, each to its own.