Building techniques changed distinctively over the centuries during which Ostia flourished
and declined. The following examples of wall facing illustrate some of the major phases of
construction at the Ostian synagogue. The changes in techniques that took place were a result
of the larger phenomenon of growth or decline in the construction industry throughout the Roman
world. Factors such as efficiency and scale of an imperial building program played a significant
role in how and why construction processes changed as they did.
Opus Mixtum A: Reticulate facing made up of small squares (conical in depth) set diagonally in
a regular net pattern, with leveling bands of lateral brick (opus latericium, usually from 3-6 courses)
at regular intervals. Quoins consist of tufa block. Mixtum A was mainly used from the mid-first through
the second century C.E. although some later examples are known, as well.
Fig.
1. A large part of the eastern half of the synagogue complex
shows Mixtum A construction. This view (shown above) of the northern
section of the West wall in room 10 is a well-preserved example. All
materials here come from natural tufa mined for building purposes. The
use of tufa and the reticulate pattern in general was common in the
earliest building phases before the method of firing clay for bricks
took hold. Construction in Mixtum A did occur at later dates, which
warns us to be cautious about dating based on the type of construction
alone.
Opus Mixtum B: Reticulate facing and latericium bands (as in Variant A), but with brickwork (latericium)
quoins. The pattern of quoins interlocking with facing is similar to Mixtum A. Mixtum B is sometimes found on
interior walls, where the exterior of same wall is faced entirely in opus latericium.
Fig. 2. This view (shown above) of the NE corner of the North wall in building
2 room 4 is a good illustration of the interlocking pattern of
reticulate facing with brick framing. Most of the western half of the
synagogue complex (including the large rooms 14 and 18 and building 2)
was constructed in Mixtum B at its earliest phase.
Opus Latericium A: Regular courses of lateral brick work for the facing of wall continuous through the quoins
and corners. Bricks are cut triangularly and vary in size. Opus latericium was used from the mid first century C.E.
onward.
Fig. 3. This close-up shot of the North wall in room 18 of the synagogue shows the regularity of the courses and the
variation in brick sizes (see figure 2 for a view of the entire wall). Opus latericium replaced
reticulatum construction for reasons of efficiency and strength; baked bricks were easy to work with and had the
endurance to support multiple storey buildings. Both of these features became necessary in the first century C.E.
when the population and building production increased drastically at Ostia.
Opus Vittatum A: Facing in alternate courses of block and brick in a 1:1 ratio. The blocks are generally well
cut and consistent in size. Vittatum A was used from the late third century C.E. into Late Antiquity.
Fig. 4. This view (shown above) is of the exterior of the Torah Niche. The
lower half of the wall shows original Vittatum A construction, while
the upper half is entirely reconstructed. Notice the regularity of the
brick and block courses. Vittatum A is the most regular of this type of
construction. The other types of Vittatum (B-C) demonstrate a much
greater degree of variation in brick and block sizes and shapes,
irregular patterns of courses, and even substitute materials for bricks
or blocks. These features suggest the reuse of earlier materials (see
figure 3) and coincide with the decline of
population and building production that occurred toward the end of the
third century onward. Vittatum construction was used mostly for repair
and renovations.
Work Consulted
Sear, Frank. 1982. Roman Architecture. Cornell University Press.
