PART 2: BRICK IN THE MIDDLE AGES

by Prof. Ing. Enrico Verdozzi

*** MANUFACTURE OF BRICK ***

(Pages: 47-48)

THE entire Medieval period affords no bibliographical sources from which to draw information on the manufacture of brick, but we may assume that the methods were doubtless much the same as in preceding period and would differ little form that employed today for hand made brick. In dimensions, there was seldom found standardize brick in which length and breadth were approximately multiples of thickness. On the contrary, there was much variation due both to tradition and to the localization in manufacturing and building practice to which Professor Giovannoni in his Preface has alluded (1). Thus at Ravenna, some of the old brick found in San Giovanni Evangelista and the tomb of Galla Placidia are 8.5, 9, and even 10 cm. in thickness [3.4, 3.5, 3.9 in.] while in San Vitale they do not run over 4.5 cm. [1.8 in.]. Later in the period, the usual thickness of the Roman brick, 3-4 cm. [1.2-1.6 in.], is found; at Bologna, in the XVII and XVII centuries, the brick are from 5 to 7 cm. thick [1.9-2.8 in.].

We no longer find the wedge-shaped brick which had already disappeared in the last period of Roman civilization and which was so prized in the construction of arches. We do find, however, bricks with one face in the form of an arc for use in columns, as seen very frequently at Bologna. There were also bricks curved flatwise to serve on the extrados of arches. These were employed a little everywhere after the X century.

Roofing tiles, both curved and flat, were also manufactured as in the Roman period, but of much smaller dimensions, approaching an average of 30 x 45 cm. [11.8 x 17.7 in.] and often even smaller. At a later period the flat tile disappeared almost entirely, as may be been in the roofs of nearly all the constructions from the XII century on.

The use of brick extended to religious and municipal buildings, and to monumental work of various kinds. There were no longer great numbers of laborers for concrete work, or great financial resources to lavish on the splendors of stone. We have, instead, above all in the first period of the Middle Ages, works constructed almost entirely of brick: brick walls, brick pavements, and brick vaults. Economy was necessary; imposing thermal edifices and huge basilicas were out of question after the fall of the Empire. There was no longer a powerful state which could exploit the labor of slaves, skillful both in construction and decoration. Hence, economy was sought both in the use of the raw material and the employment of labor. The mason, however, will become more skillful, while the architect will have at his disposal very modest means for the work to be accomplished, and will attain a lightness of construction hitherto unknown, as well we shall see in the examples to be examined which have remained intact in spite of the succession of various states of culture in the same regions.

We shall find vaults covering limited spaces with clever solutions hitherto unknown, because not required of the Roman architect. We shall see cornices, at first and for a long time afterward, as artificial arrangements of brick; then to evolve slowly into a very pure feeling which will become the constant characteristic of brick construction.

Both in the V century when Honorius, the first Emperor of the West after the final division of the Empire, removed his residence from Rome to Ravenna (403), and in the following century when Justinian, Emperor of the East, having recovered Sicily and Italy, also chose that city as the seat of his Exarch (539), it was natural that the little city should rise to great importance and that, in the consequent building activities, the Byzintine influence should be marked. It was during this disturbed epoch that there arose a new form of art which developed no longer at Rome at his center, but at Ravenna. Here we find famous architectural monuments which forms peculiar to the Roman period, but with an altogether new feeling.

In construction, the simple brickwork of the exterior walls, with varying mortar joints, was no longer so carefully done, as if the artisans had hastened in order to devote themselves with the utmost zeal to interior decoration.

As a decorative motive in cornices, there prevailed a practice of setting the bricks corner to corner in saw-tooth fashion, often between regular courses.

Wall surfaces were frequently embellished with blind arches and pilasters resting upon a base which ran around the entire edifice, but which today is for the most part sunk in the earth, chiefly because of the settlement to which the structure have been subjected. We mention a few of the more characteristic monuments in chronological order.

San Giovanni Evangelista, founded in the year 425 by Galla Placidia (2), but entirely rebuilt later, has, in the external wall of the central nave, an order of small blind arcades supported by slender pilasters resting upon a light, continuous base. Above , a certain decorative effect was sought in a row of small pendants arches. We shall find these motives characteristic of brick architecture during this period, and later shall find them developed into various forms of expression throughout the Middle Ages.

The Mausoleum of Galla Placidia, founded by that princess and originally known as Santi Nazario e Celso, dating from 440, is built of brick greatly differing in dimensions, among which those running 8 x 30 x 15 cm. [3.2 x 11.9 x 5.9 in.] and others, not standardized (3), measuring 10 x 43 x 25 cm. [3.9 x 16.9 x 9.8 in.] predominate. For the arches, thinner bricks were used.

The dome (volta a vela) (4)over the central compartment is constructed of bricks set normal to the direction of the vertical curve, a process of construction which we see here applied for the first time in history of building. The reinforcing of the dome as well as of the barrel vaults, in the four arms of the cross, consists of amphorae or terra cotta wine jars of various sizes, which followed the slope of the roof so that a little mortar between, the roofing tiles could be laid upon them. The stamps upon these tiles were clearly visible in the recent restorations of this famous monument.

Of special interest is the exterior decoration of the Chapel of San Pier Crisologo (433-449) showing small pendent arches, each of which is supported by a bracket of cut brick. Worthy of notice are the wall divisions, adorned with these small arches which are separated into twos and fours by pilasters supported on a continuous base. The cornice is characteristic of this period.

The Baptistery of Neone (Italian link), also known as the Battistero Ortodosso or San Giovanni in Fonte (449-458), reveals sober and dignified lines. The simple motives of the arched windows and blind arcades are very effective. The cornice, ..., consists of the usual row of brick in the saw-tooth fashion, between two even courses. We have here the first example of a dome, concealed on the exterior as in Galla Placidia, composed of superimposed rows of small terra cotta pipes instead one into the other. Of the same period is the interesting Baptistery of the Aians, afterwards the Oratory Santa Maria in Cosmedin. It is said to have been originally the octagonal half of a Roman bath.

In Sant' Apollinare Nuovo, founded by the Emperor Theodoric as an Arian church about 520 and known as Sanctus Martinus in Coelo Aureo until the VIII century, there is a certain attempt at decorative effects in the small projecting arches under the eaves of the nave wall. This is a motive which, developed into a notable perspective expression, may be found two centuries later in the so-called Royal Palace, or Reggia ad Calchis, built on the ruins of the Palace of Theodoric.

San Vitale, an octagonal dome edifice, built 526-537 by Julianus Argentarius, was begun under Theodoric and completed under Justunian. In his " History of Architecture", Fletcher states that it was molded after the so-called Minerva Medica of Rome, a decagonal Nympheum of the Imperial epoch. The bricks vary in thickness from 3.5 to 4.5 cm. [1.4 to 1.8 in.], with the other dimensions conforming to no standard, the length 34 x 51 cm. [13.4 x 20.1 in.] however predominating. Where new brick have been required for restorations, they have been brought from Imola to meet the requirements of quality. The mortar joints vary from 2 to5 cm. [0.8 to 1.9 in.], that is, sometimes wider than the thickness of the brick. The crown cornice is composed of five courses of brick, two of which are set saw-tooth fashion in alternation with the other courses. The lower cornice, which is interrupted by the lunette of the XV century portal and masks the division the two stories on the interior, consists simply of three brick courses the center one of which is saw-tooth.

The buttresses at the angles of the main octagon which measure 1.58 m. in width by 1.25 m. in projection [5 ft. 2in. x 4 ft 1 in.], are worthy of note. They are joined by means of brick arches, concealed by the roof, to the pilasters of the cupola. The intermediate pilasters, having a projection of 32 cm. and a width of about 94 cm. [12.6 x 37 in.], form other vertical lines which rise far enough to intersect the crown cornice.

Moreover, a new motive in the architecture of Ravenna may be seen in the two corbeled brackets at the extremities of the apse gable. The cupola is constructed of terra cotta wine jars which form a true spiral coming to a close at the summit.

Sant' Apollinare in Classe is another very important monument of the VI century, also constructed by Julianus Argentarius, and on the basilican plan. The brick of a light red tone are 3.5-4 x 50 x 34 cm. [1.4-1.6 x 19.7 x 13.4 in.] with mortar joints running from 2 to 5 cm. [0.8-2 in.] in thickness (5). Here also the sides are decorated with a blind arcade of small round arches corresponding to the interior round-arched arcades, but without any indication of capitals, except in the central nave, on the exterior walls of which may be seen at the impost three projection in as many rows of brick. The apse has the usual brick cornice in saw-tooth between regular courses.

The campaniles at Ravenna are later than the IX century, with the exception of the circular towers of Sant' Apollinare in Classe and Sant' Apollinare Nuovo, which belong to that period. In origin, the campanile of Sant' Agata, goes back to the earlier period, but as seen today represents a reconstruction of the XV century. The bell tower of Santi Giovanni e Paolo, is perhaps the earliest of all, dating as far back as the VI or VII century. The square campaniles of San Giovanni Evangelista and San Francesco belong to the IX century. Somewhat later is the campanile of Santa Maria in Porto Fuori, which rises from a massive base said to have belonged to an ancient light-house.

The tower of Sant' Apollinare in Classe, about 40 meters high [131 ft.] with walls 1.5 m. thick [5 ft.] is built of bricks of very different dimensions, some of which probably came from demolished buildings. A few traces of horizontal cornices are preserved and each story has openings of one-, two- or three arched lights. The campanile of Sant' Apollinare Nuovo, like the preceding, has cornice lines at each story either saw-tooth or simple bands of projecting brick. The crown cornice is made up of two saw-tooth courses which alternate with regular courses. Another characteristic decoration, which has partly disappeared, is here composed of bowl-like ornaments of glazed terra cotta, of which two may be seen over the last three light opening, with relief in green, red, and old gold at the centers. The varied treatment of the same motives in the campanile of Sant' Agata is worthy of note.

In other localities contiguous to the Romagna, we find the same forms established at this time. At Pomposa, in the province of Ferrara, the Church of Santa Maria was built in a manner absolutely similar to the monuments mentioned thus far, with the two characteristic bracket-shaped projections at the extremes of the gable, as we see in San Vitale and Sant' Apollinare in Classe. The portico, added in 1026, is also in brick of the prevailing type, and bears upon its face detailed symbolical bas-reliefs which form a beautiful decoration. Of special interest is the campanile 50 meters [164 ft.] in height, built in 1063. It follows faithfully the forms of the past with the exception of some details of the cornices and the round majolica ornaments which are found in great profusion.

The Pieve (Parish Church) of Bagnocavallo, between Faenza and Imola, belongs to the V or the VI century at the latest. This church was also built in the same manner and with the same materials as the churches of Ravenna. It reminds us forcibly of the Basilica of Sant' Apollinare in Classe both because of the two projections at the extremities of the gable and the elevation of the walls of its façades above the roof, meant to give greater elegance and slenderness to the edifice. The well-preserved sides are decorated on the exterior of the central nave with the usual series of small blind arches, having alternate pendent supports while the pilasters rise from a band a little above the roof of the aisles. Above the small arches is the usual cornice of a saw-tooth course between two flat courses. The round campanile of the IX century was destroyed at an early date.

San Lorenzo Maggiore at Milan also goes back to the VI century. On the exterior of the original wall is a brick facing ornamented at the sides with pilasters corresponding to the interior arcades as in San Vitale. The edifice as it appears today is due to a reconstruction of the XVI century, following the forms of the original, upon the same foundations. With an octagonal plan, it is reinforced at the corners by sturdy buttresses.

Many other edifices, originally built of brick, have almost totally lost their real physiognomy, as has happened, to cite one of the greatest examples, in case of St. Mark's at Venice.