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 p769  Murus

Article by Leonhard Schmitz, Ph.D., F.R.S.E., Rector of the High School of Edinburgh
on pp769‑772 of

MURUS, MOENIA (τεῖχος), the wall of a city, in contradistinction to Paries (τοῖχος), the wall of a house, and Maceria, a boundary wall. Both the Latin and Greek words appear to contain, as a part of their root meaning, the idea of a firm, strong wall; and they nearly always used for walls of stone or some other massive construction. Murus and τεῖχος are also used for the outer wall of a large building.

We find cities surrounded by massive walls at the earliest periods of Greek and Roman history, of which we have any records. Homer speaks of the chief cities of the Argive kingdom as "the walled Tiryns," and "Mycenae the well-built city" (Il. II.559, 569), not only thus, as in other passages, proving the common use of such structures in the Homeric period, but also attesting the great antiquity of those identical gigantic walls which still stand at Tiryns and Mycenae, and other cities of Greece and Italy. In Epirus, in  p770 Etruria, and in Central Italy, especially in the valleys at the foot of the Apennines on their western side, we find numerous remains of walls, which are alike, inasmuch as they are composed of immense blocks of stones put together without cement of any kind, but which differ from one another in the mode of their construction. Three principal species can be clearly distinguished:—

1. That in which the masses of stone are of irregular shape and are put together without any attempt to fit them into one another, the interstices being loosely filled in with smaller stones; as in the walls of the citadel of Tiryns, a portion of which is shown in the following engraving:—

Another specimen of the buildings at Tiryns, of much more regular construction, may be seen at p125.

2. In other cases we find the blocks still of irregular polygonal shapes, but of a construction which shows a considerable advance upon the former. The stones are no longer unhewn (ἀργοί λίθοι), but their sides are sufficiently smoothed to make each fit accurately into the angles between the others, and their faces are cut so as to give the whole wall a tolerably smooth surface. Examples of this sort of work are very common in Etruria. The engraving is taken from the walls of Larissa in Argolis.

3. In the third species, the blocks are laid in horizontal courses, more or less regular (sometimes indeed so irregular, that none of the horizontal joints are continuous), and with vertical joints perpendicular or oblique, and with all the joints more or less accurately fitted. The walls of Mycenae present one of the ruder examples of this sort of structure; and the following engraving of the "Lion Gate," of that fortress (so called from the rudely sculptured figures of lions) shows also the manner in which the gates of these three species of walls were built, by supporting an immense block of stone, for the lintel, upon two others, for jambs, the latter inclining inwards, so as to give more space than if they were upright. A very large number of interesting examples of these constructions will be found engraved in some of the works presently referred to.

We have only space for these three characteristic specimens, one of each class. Neither is it here possible, or at all necessary, to discuss the opinions of ancient writers, most of whom were content with the popular legend which assigned these works to the Cyclopes, nor the theories of modern scholars and antiquarians, who (with some of the ancients) have generally referred them to the Pelasgians. The principal conclusions to which Mr. Bunbury has come, from a thorough examination of the whole subject, may be safely regarded as correct: namely, that while in such works as the walls of Tiryns we have undoubtedly the earliest examples of mural architecture, it is quite a fallacy to lay down the general principle, that the unhewn, the polygonal, the more irregular and the more regular rectangular constructions, always indicate successive steps in the progress of the art; and that it is also erroneous to assign these works to any one people or any one period; that, while such massive structures would of course be built by people comparatively ignorant of the art of stone-cutting or of the tools proper for it, they might be and were also erected in later times simply on account of their adaptation to their purpose, and from the motive of saving unnecessary labour; and that the difference between the polygonal and rectangular structures is generally to be ascribed not to a difference in the skill of the workmen, but to the different physical characteristics of the material they employed, — the one sort of structure being usually of a species of limestone, which easily splits into polygonal blocks, and the other a sandstone, the natural cleavage of which is horizontal. (Bunbury, Cyclopean Remains in Central Italy, in the Classical Museum, 1845, vol. II pp147, &c.; Müller, Archäol. d. Kunst, §§45, 166, and the works there quoted; Stieglitz, Archäol. d. Baukunst, vol. I pp95‑98; Hirt, Gesch. d. Baukunst, vol. I pp195, &c., and plate VII. from which the foregoing cuts are taken; Atlas zu Kugler's Kunstgeschichte, Pt. II Pl. 1; Göttling in the Rhein. Mus. 1843, vol. IV pp321, 480, and in the Archäologische Zeitung, No. 26; Pompeii, vol. I c4, with several woodcuts of walls; Abeken, Mittelitalien vor den Zeiten römischer Herrschaft, a most important work, with numerous engravings of walls).

The examples of the foregoing class lead us gradually to the regular mode of construction which prevailed in Greece after the time of the Persian Wars, and which had been adopted in the walls of temples much earlier. In the long walls of  p771 Athens, and the walls of Peiraeeus, the massiveness of the Cyclopaean works was united with perfect regularity of construction. The stones, which were so large that each was a cart-load (ἁμαξιαῖοι), were accurately fitted to one another (ἐν τομῇ ἐγγώνιοι), and held together, without cement by metal clamps and soldered with lead into sockets cut into the blocks of stone (Thuc. I.93). The walls of the Parthenon, and the other great edifices of the period, were of similar construction. Sometimes wooden plugs were used instead of metal clamps. It is unnecessary to describe here the details of the modes in which the joints were arranged in this regular and massive masonry. So perfect was the workman­ship at this period of the art, that the joints often appeared like a thread; and Pliny mentions a temple at Cyzicus, in the interior wall of which a fine thread of gold was actually inserted in the joints of the masonry (Plin. H. N. XXXVI.15 s22).

The materials employed at this period were various sorts of stone, and, in some of the most magnificent temples, marble. The practice of putting a facing of marble over a wall of a commoner material was introduced in the next period of architectural history. The first example of it, according to Pliny (H. N. XXXVI.6 s6), was in the palace of Mausolus, the walls of which were of brick, faced with slabs (crustae) of Proconnesian marble (about B.C. 360). Vitruvius (II.8) also states this fact, and adds that brick walls, when perfectly perpendicular, are quite as durable as those of stone, and, in proof of this, he mentions several examples of very ancient brick buildings, both in Greece and Italy (cf. Vitruv. I.42; Paus. I.42, II.27, V.5, X.4, 35; Later.)

For buildings of a common sort, the materials employed were smaller stones, rough or squared, or flints, as well as bricks: the latter, however, were not nearly so much used by the Greeks as by the Romans. The different methods of construction will be described presently.

The walls of smaller quarried stones or bricks were bound together with various kinds of mortar or cement, composed of lime mixed with different sans and volcanic earths. The most durable of these was the cement formed by mixing two parts of Terra Puteolana (Puzzolana, a volcanic product, which is found in various parts of Italy, besides Puteoli) with one part of mortar: this cement had the property of hardening rapidly under water: it was much used in aqueducts, cisterns, and such works. (For further details on cements, see Vitruv. II.5, 6, V.12, VII.2; Plin. H. N. XXXVI.23 s52, 55; Pallad. I.10, 14; Strab. V p245; Dioscor. V.133).

The history of Roman masonry is not very different from that of the Greek. The Cyclopean remains of Italy have already been noticed. The most ancient works at Rome, such as the Carcer Mamertinus, the Cloaca Maxima,º and the Servian Walls, were constructed of massive quadrangular hewn stones, placed together without cement. [Cloaca.] In most of the remains, the stones are twice as long as they are high. Canina (Arch. Antiq.) distinguishes five species of Roman masonry; namely, (1) when the blocks of stone are laid in alternate courses, lengthwise in one course, and crosswise in the next; this is the most common; (2) when the stones in each course are laid alternately along and across; this construction was usual when the walls were to be faced with slabs of marble; (3) when they are laid entirely lengthwise; (4) entirely crosswise; and (5) when the courses are alternately higher and lower than each other, as in the round temple (of Vesta, so called) upon the Tiber. This temple also affords us an example of what is called rustic-work, in which the stones are bevelled at their joints, the rest of their surfaces being generally left rough. This style of work originated, in the opinion of some, from the desire to save the trouble of smoothing the whole face of the stones; but it is more probable that it was adopted in order to give a bolder and firmer appearance to the structure. Examples of it are found in the remains of several Roman fortifications in Germany, and in the substructions of the bridge over the Moselle at Coblenz (Rhein. Mus. 1836, vol. IV p310; Witzschel, in the Real-Encyclop. d. class. Alterth. art. Muri). As by the Greeks, so by the Romans, walls of a commoner sort were built of smaller quarried stones (caementa) or of bricks. Vitruvius (II.8) and Pliny (H. N. XXXVI.22 s51) describe the following kinds of masonry, according to the mode in which the small stones (caementa) were put together. (The woodcut is copied from the Abbildungen zu Wincklemann's Werke, Donauöschingen, 1835, fig. 10).

Besides the large square blocks of stone (O), they used smaller quadrangular stones arranged in regular courses of equal and unequal heights; the former was called isodomum (M), the latter pseudisodomum (L); in another sort of work, called emplecton (G), the outer faces of the walls only were of wrought stones, the intermediate parts being filled up with rough stones, but these, in the Greek method of construction, were well bedded in mortar, and arranged with overlapping joints, and the wall was bonded together with stones laid across at intervals, which were called διάτονοι (F); but the workmen of the time of Vitruvius were in the habit, for the sake of despatch, of running up the outer walls separately, and then filled the middle space with loose rubbish, a sort of work which Pliny calls diamicton. The excellence of the cement which the Romans used enabled them to construct walls of very small rough stones, not laid in courses, but held together by the mortar; this structure was called opus incertum (N). An improvement upon it in appearance, but inferior in stability, was the opus reticulatum, of which there were two kinds, the like (K) and the unlike (I). This sort of work was composed of stones or bricks, from six to nine inches long, and about three inches square at the end, which formed the faces of the  p772 wall, the interior being filled in with mortar and small rough stones. Vitruvius complains of these walls as being apt to split, on account of their having neither horizontal courses nor covered joints. Another structure of which the Romans made great use, and which was one of the most durable of all, was that composed of courses of flat tiles (H). Such courses were also introduced in the other kinds of stone and brick walls, in which they both served as bond-courses, and, in the lower part of the wall, kept the damp from rising from the ground. Brick walls covered with stucco were exceedingly common with the Romans: even columns were made of brick covered with stucco; we have an example in the columns of the basilica at Pompeii, the construction of which is explained in Pompeii, vol. I p136. In hot countries, as in Africa and Spain, walls were built of earth rammed in between two faces or moulds (tabulae, formae), which were removed when it hardened; they were called parietes formacei; and Pliny mentions watch-towers of this construction, built by Hannibal, on the mountains of Spain, which still stood firm (H. N. XXXV.14 s48). Walls of turf were chiefly used in the ramparts of camps (Agger, Vallum) and as embankments for rivers.

With respect to the use of walls as fortifications, we have not space to say much. The Cyclopean walls of Tiryns, &c. had no towers; but Homer refers to towers on the walls of Troy; and in the historical period we find that it was the practice to furnish walls with towers at regular intervals. Some writers on military affairs recommend them to be placed at salient angles of the walls, in order to command the intervening spaces, whilst others object to this position on account of the increased exposure of the tower itself to the battering ram. The account which Thucydides gives, in his second book, of the siege of Plataeae, is an interesting exhibition of the state of the science of fortification and attack at the period of the Peloponnesian war. Much was done to advance it by the architects and engineers of the time of Alexander and his successors. The rules which have been established by the time of the Roman emperors may be seen exhibited in detail by Vitruvius (I.5), and the writers on military affairs, and illustrated by the remains of the walls of Pompeii (Pompeii, vol. I pp66, &c.). The system may be described in a few words as a broad terrace of earth (agger) enclosed between two battlemented walls and furnished with towers, two, three, or more stories high, communicating by arched doorways with the agger, and also having a sally-port. These towers were at distances, on the average, of the cast of a javelin, but varying according to the greater or less exposure of each part of the wall. Respecting the gates, see Porta.

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Thayer's Note:

For a more practical approach, with 3 good illustrations, to the vallum, see this section of John Pollen's book, The Trajan Column.

Images with borders lead to more information. The thicker the border, the more information. (Details here.)
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