Londinium, Architecture and the Crafts

by W. R. Lethaby

Masonry.—Walling had three main origins in mud, timber and stone. Walling stones were at first, and for long, packed together without mortar. Mud and stone were then combined; later, lime mortar took the place of mud, being a sort of mud which will set harder. In concrete, again, the mortar became the principal element. Stone walling was at first formed of irregular lumps. When hewn blocks came to be used a practice arose of linking them with wood or metal cramps. There are also three main types of wall construction—aggregation of mud, framing of timber, and association of blocks of stone. A later development of mud walling was to break up the material, by analogy with hewn stone, into regular lumps separately dried before they were used; thus crude bricks, the commonest building material in antiquity, were formed. Roofing tiles were developed from pottery, and such tiles came to be used for covering the tops of crude brick walls. Then, later, whole walls were formed of baked material, and thus the tile or brick wall was obtained. An alternative method of using mud was to daub it over timber or wattle (basket work) of sticks; and this seems to have been a common procedure in Celtic Britain.

Interesting varieties of concrete walling were developed by Roman builders. One of these was the use of little stones for the faces of a wall, tailing back into the concrete mass and forming a hard skin or mail on the surfaces, very like modern paving. Triangular tiles with their points toothed into the concrete mass were also used. Then tile courses were set in stone and concrete walls at every few feet of height.

I have been speaking of general principles and history, not limiting myself to Britain and Londinium, but the evolution of the wall is an interesting introduction to our proper subject.

Fig. 1.

In Londinium wrought stonework must have been very sparingly used because of the difficulty and cost of transit. There were columns, pilasters, plinths, cornices, etc., but it may be doubted whether there were any buildings other than small monuments wholly of such masonry. Even in the first century the “details” of masonry were far from being “correctly classical,” and ornaments were very redundant and inventive. Provincial Roman building was something very different from the grammars propounded by architects. As we may study it in the fine museums of Trèves, Lyons, and London, it seems more like proto-Romanesque than a late form of “classic.” The Corinthian capitals of Cirencester are very fine works indeed; the acanthus is treated freshly, the points of the leaves being sharp and arranged as in Byzantine work; a sculptured pediment and ornamental frieze at Bath are also free and fine. On the other hand, moulded work is usually coarse and poor. An interesting architectural fragment found in London was the upper drum of a column which had several bands of leafage around the shaft and was a remote descendant of the acanthus column at Delphi (Fig. [1]). Parts of small columns and their bases have been found, the latter with crude mouldings. I mention them because small circular work was usually turned in a lathe like Saxon baluster-shafts. A small capital from Silchester in the Reading Museum is of the bowl form so characteristic of Romanesque art.

Fig. 2.

A few fragments of mouldings and other stones are in our museums (Fig. [2]), and a considerable number of semicircular stones have been found which must have been copings. Large wrought stones were usually cramped together; lewis holes show how they were hoisted; smaller wall-facings were, I think, cut with an axe instead of a chisel. We find mention of one stone arch (a small niche?) in a Minute of the Society of Antiquaries: “Mar. 8, 1732: Mr. Sam Gale acquainted the Society, yt in digging up some old foundations near ye new Fabric erected Anno 1732 for ye Bank of England Mr. Sampson ye architect discovered a large old wall, eight foot under ye surface of ye ground, consisting of chalk stone and rubble, next to Threadneedle Street, in which was an arch of stone and a Busto of a man placed in it standing upon ye plinth, which he carefully covered up again: there was no inscription but he believed it to be Roman.”

Mortar and Concrete.—Roman builders early learnt how to make good mortar and concrete, being careful to use clean coarse gravel and finely divided lime. They also found that an addition of crushed tiles and pottery was an improvement, and for their good work used so much of this that the mortar became quite red. “Roman mortar was generally composed of lime, pounded tiles, sand and gravel, more or less coarse, and even small pebbles. At Richborough the mortar used in the interior of the walls is composed of lime and sand and pebbles or sea-beach, but the facing stones throughout are cemented with a much finer mortar in which powdered tile is introduced” (T. Wright).