Londinium, Architecture and the Crafts

by W. R. Lethaby

Fig. 29. See p. [61].

Fig. 30.

In September 1903 an important section of the Roman wall was found in excavating the site of Newgate Prison; in some parts it was about a dozen feet high. I saw it in October and noted—“The wall is about 8½ ft. wide. On the outside and inside one or two courses of facing stones were first raised and the core of rubble was then filled in to that height; first there was a thick couch of mortar, then a layer of rubble stones, then another liberal supply of mortar running down between the stones as grout; there were two or three such levellings-up in the heights between the tile bonding courses.” The wall had a rough rubble foundation, then a course of plinth stones on the outside, with three tile courses corresponding to it on the inside of the wall, then followed five courses of the fairly square facing stones on both sides of the wall, then two rows of tile, five courses more stone and two rows of tile, then five more stone courses; above this level the wall had been destroyed. The stones and tiles were set in mortar, and the latter, except for the three courses at the bottom on the inside, which served as a plinth, were carried right through the thickness of the wall; the “tiles” were Roman bricks about 18 in. by 12 in. and 1½ in. thick, laid in what we call Flemish bond. The stone facing courses were a little higher at the bottom than upwards, but all were comparatively small and square; there was a clear distinction between the wrought facings and the rubble filling, which was practically concrete. The “facings” were hard skins adhering to the filling and required by the method of building as described above (Fig. [30]).

The mode of construction of the wall is likely to be misunderstood when we speak as we almost necessarily do of facings and filling and of bond tiles. The “facing” stones were small, roughly wrought, and set in much mortar; they formed outer skins to the concreted mass into which they tailed back. The whole was homogeneous. The method was analogous to the facing of concrete with triangular bricks notching back into the core.

The tile courses in the City Wall were doubtless bonds, but they also divided the wall into strata locking up the moisture of the mortar from too rapid absorption and evaporation. I have little doubt that the wall was carried up a stratum at a time over long lengths; it would thus have been available as a defence from an early stage, and scaffolding would not have been required. The building of this wall and casting the ditch about it required a great constructive effort. A strip of ground some 100 feet wide must have been cleared as a preliminary. Then the immense quantity of stone required would have been brought by ships and barges. It is often said that old material was not re-used in the wall, but I can hardly think that two miles of chamfered plinth had to be provided out of new stone at the very beginning of the work. And material from destroyed monuments was doubtless broken up for the small facing stones. The lime-burning, brick-making, stone-cutting, as well as the actual building, called for much labour. It would be interesting to have the quantities taken out and an estimate prepared.

The south wall along the river front is well described in V.C.H. Roach Smith, in an article in vol. i. of the Archæological Journal, recorded the fact that it had “alternate layers of red and yellow plain and curve-edged (i.e. flanged) tiles”; the rest being of ragstone and flint. It was founded on piles. In The Builder (January 19, 1912) it is recorded that in digging for a foundation at No. 125 Lower Thames Street, between Fish Street Hill and Pudding Lane, there was found the base of the Roman wall resting upon long and thick timber balks laid crosswise, with piles beneath them; there were three courses of rough rag and sandstone capped with two courses of yellow bonding tiles, all in reddish mortar; what remained was about 3 ft. high and 10 ft. wide, and was at 24 ft. below the existing pavement. Full evidence of the course of the City Wall along the river front has been found (Archæol. xliii.). It may be noticed that in mediæval regulations foreign sailors might not go beyond Thames Street; that is, pass where the wall had been, into the City proper. This south wall, like the bastions, contained remnants of Roman monuments.

The south wall would have been interrupted at the outlet of the Walbrook, which must have been a tidal creek. This was doubtless the original harbour, and there would have been quays within the line of the wall. Daremberg and Saglio’s plan of Bordeaux shows a remarkable parallel to Londinium, standing on the bank of a great river, flanked by a little stream and with a port within the walls (Fig. [29]). It seems probable that the strong wall which Roach Smith reports as having been found on the east side of the Walbrook may have been a quay wall. The Thames has been much encroached on where it passes the City. In making the approach to new London Bridge three successive embankments were found, one being of squared trunks of trees. A similar timber wall has just been found in Miles Lane. In Lower Thames Street the Roman house found on its north side was built on piles, “probably on the river bank” (Athen., 1848), and the south City Wall was wholly built on timbering. In earlier Londinium, Cannon Street must have been the southern thoroughfare.

Bastions.—In July 1909, when the angle bastion near Giltspur Street was excavated, I noted that close to it the City Wall was badly fractured, and inclined outwards; there had evidently been a serious settlement here, which was sufficiently accounted for by the nature of the ground—wet clay on the bank of a stream. The wall was taken lower than the ordinary level here, and the bastion was founded at a lower level still. The bastion was not bonded to the City Wall, but merely built against it with a straight joint; it was of horseshoe shape on plan and projected about 27 ft., the masonry was rubble in thin courses, and the whole looked mediæval to me. In the careful report in Archæologia it was said that some evidence for Roman date was discovered in the foundation. The facts suggested to me not only that the bastion had been built against the wall, but that it was probably built at a point of failure in the original wall. It is agreed that the bastions were built later than the wall, and with a straight joint between them and it, and I would suggest that they were built to cover cracks and form buttresses as well as for their additional defensive value, and this may very well have been the general procedure. It would have been impossible to build a wall measured by miles on inferior foundations without bad settlements; the Egyptians provided for them by building such walls in sections with inclined straight joints at intervals.

M. Blanchet, writing of the walls of the cities of Gaul, says: “Often the curtains are not bonded with the towers. This independence reminds one of a precept of Philo’s, which advises that the method should be followed so as to prevent the consequences of unequal settlement between the two. But there is a more simple explanation—the town under immediate danger ensures itself first with the curtain and adds the towers after. Most of the fortifications are those which the Romans built on the approach of the Barbarian invasions. To this period belong the walls of Rome and those of the cities of Gaul.” Choisy again has an interesting account of the towers of the walls of Constantinople, with a diagram of arches in the sides of the towers at the ground level, which were built so that the effective part of their foundations should be kept clear of the wall. Now, the foundations of the London bastions provide evidence of a similar way of thinking.