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Topographical dictionary - Building glossary

Drawing of part of a measure (Roman foot), made of bone, found in or near Via della Fontana in 1897.
Front (above) and back. NSc 1897, p. 524.

A bit more than half of the measure has been preserved. Originally it was 29.6 cm. long.
The original centre is at the right end and indicated by a line flanked by two triangles.

A brick stamp. Photograph: Jan Theo Bakker.
Opus latericium (wall facing)

Brickfaced masonry. If exceptionally a field of reticulate is visible (small tufa blocks placed diagonally), the whole may still be described as opus latericium.

From Augustus (only specific constructions such as corridors, wells, nymphaea etc.) until Theoderic.

Opus mixtum: see Opus reticulatum mixtum
Opus reticulatum (wall facing)

Small tufa blocks placed diagonally. The whole wall consists of these tufa blocks. Exceptions: necessary framing of windows, doors etc., and occasional reinforcing of corners of buildings, with oblong tufa blocks.

Late Republican, early Principate until Nero.

Opus reticulatum mixtum or Opus mixtum (wall facing)

Masonry of reticulate (small tufa blocks placed diagonally) reinforced and/or intersected by brick bands (normally five to six courses). The reticulate and the bricks are sometimes interlocking. The reticulate fields are rather large.

Flavians and throughout second century, declining with the Antonines.

Opus signinum (floors and walls)

Waterproof floor- and wall-revetment consisting of mortar mixed with terracotta sherds and crushed tiles or bricks.


Opus sectile (floors and walls)

Decoration of walls or floors with marble slabs laid in a regular pattern.


Opus spicatum (floors)

A floor made of quite small, elongated tiles, laid in a herringbone pattern.


Opus vittatum mixtum (wall facing)

Oblong or occasionally square tufa blocks intersected by one or more brick bands, at regular or irregular distances. Square blocks (re-used reticulate blocks) appear mainly in third century masonry. After that they disappear as building material. Opus vittatum mixtum has two subgroups: A and B. The distinction is made purely for chronological reasons.

From the Severan period throughout late antiquity.


Opus vittatum mixtum A (wall facing)

Alternating oblong tufa courses and brick bands, 1:1. Tufa blocks usually rather well cut (compared to B).

From the early third century throughout late antiquity. Main appearance in the third and fourth century.

Opus vittatum mixtum B (wall facing)

Alternating oblong tufa courses and brick bands, in all other combinations than 1:1. Oblong, often rather egg-shaped tufa blocks appearing in an irregular number of courses, and alternated at irregular distances with one or more courses of brick.

Main appearance in later fourth century. Continuing until the Mediaeval period.

Opus vittatum simplex (wall facing)

Oblong tufa blocks without any other interference. Blocks very well cut during the Republic and early Principate. From the last decades of the Republic mostly found in combination with opus reticulatum. In late antiquity an increasing tendency to egg-shaped blocks, which appear in the fourth century.

From the Republic until Nero. Re-appears in the third century.

[Jan Theo Bakker and Thea Heres]