A series of information panels outside the Museum of London would provide as near definitive an answer to my query as I could reasonably hope for. As I learned then, I had arrived at the Wall’s western limits by unknowingly tracing the Wall’s unseen northern length. From my elevated position on the walkway, I looked down on a line of ruined bastions, from each of which the back wall had been removed. Perhaps in the interest of space, the city planners had also seen fit to thin the retaining wall from its original width of a meter to that of what looked a handspan.
I turned back to the information panel to compare what lay before me with what I could find in text. It would seem that on the ground below where I now stood, the Romans had erected a rectangular fort at the beginning of the second century after Christ. To this fort, a hundred years later, they joined a stone wall to set off Londinium from the plains around.
I had difficulties fathoming the scale of the work in the description given: more than three kilometers in length, almost three meters in thickness and six in height, and greater still in places. For each of the Wall’s more than fifty thousand square meters, builders could not have found a stone, perfectly cubed, and so would have resorted to collecting stones wherever they might find them, numbering in the hundreds of thousands or even millions, drawing them when possible from the nearest quarries, but otherwise from surrounding fields, streams and woods. If the overseers had charged each living soul in Londinium with collecting but one stone to add to the pile, the Wall would only have grown as fast as its churchyards.
As the fort sat at the northwestern extremity of the young settlement, the fort’s northern and western walls naturally became part of the city’s landward fortifications. As with all undertakings requiring a certain breadth of vision, work did not end there, and Roman engineers continued to build on riverfront walls and bastions, ditches and earthworks. The sign before me noted that these same engineers had added outer bastions to the Wall’s eastern stretch in order to reinforce the defenses but had not pursued this project with the western. Though the sign left the reason unmentioned, I, like other readers, might reasonably attribute it to the project’s date in the late fourth century, not long before the Angles’ arrival on those shores.
Given the above, the bastions, hulled and open to the sky, could not be the work of Roman hands and had, by all accounts, risen during the city’s medieval period, perhaps as early as the thirteenth century. In addition to being of later date, they had the particularity of being hollow, be it to save on materials or to facilitate the passage of men and arms. From my perch, the earth and gravel floor was clearly visible within the half-circle of brick supporting walls; what appeared to be a walkway emerged from the wall halfway up one side and perhaps once led to a door. About the brick interior wrapped an external shell of small stones and mortar. I could detect no signs of life about the ruin beyond a green rubbish sack and sentinel pigeons.
I moved from the sign before me to another, farther down the elevated walkway, though scratched almost beyond the point of recognition. If I might imagine that some youth or other, confounded by the historian’s desire to chronicle all, had lashed out in rage and frustration at the latter’s public works, the truth more likely held out as much simpler, the work of a few vandals wielding penknives and stricken by boredom.
Beneath the long white scoring, I could still make something of the explanations and learned, to some surprise, that the thinned wall below, far from being Roman, was an eighteenth century remnant of the Barber Surgeons Hall, which had abutted the Wall. Like other moderns, the City’s Barber Surgeons had not been content to pitch their tents, as it were, in sight of the Wall but had instead joined their halls to the very structure marking out the limits of their society and, by extension, their association.
Although the Roman masonry and groundwork had vanished underground and underfoot with the modern incorporation of new buildings to old materials, that same Roman wall had continued to structure the city’s development and growth in the years to come. All of this went a long way in showing how the arbitrary marks and divisions made by one group could prove determinative for another with no link to them, effective, emotive, and so on. In such a way, the lines drawn by the geographer exercise a dread hold over the imagination, which later individuals had the utmost difficulty loosening. With this thought, my purpose in London became clearer, for I thought to find there under just what conditions that historical and geographical mania might be exorcised.