Change in Roman Architecture
Using this new technology, building could now be accomplished more rapidly and economically, and a great change took place in architecture. Cement could be formed within and over timber frameworks and so be used for such difficult construction as vaulting. The facing of cement walls usually consisted of smooth, irregularly shaped stones (opus incertum), of squared stones set on edge to form a neat network pattern (opus reticulatum, shortly after 100 BC), or of baked bricks (opus testaceum, from c.30 BC). These facings frequently provided the base for stucco or marble incrustation. Complex sequences of interior spaces with increasingly daring vaults and domes were constructed in the 1st and 2d centuries in baths, market buildings, and palaces; more and more of the traditional building types, such as temples and basilicas, were reshaped under the influence of the cement vault. The best-preserved example is the Hadrianic Pantheon (c.118-28; Rome), the temple to all the gods, with its huge, coffered-concrete dome spanning 43.3 m (142 ft).
The conventional forms of Etruscan and Greek architecture still continued to be used for many purposes. Originally prevalent in temples until the later Republic, the Tuscan order began to absorb some elements of the Greek Doric order and became Roman Doric.
The Greek Ionic order, and more so the Corinthian order, was widely used in Italy from the 2d century BC on. Probably in Augustan times elements of the Ionic and Corinthian capitals were fused.
A late-Republican development destined to have great success was the framing of the round arch with a superposed and generally engaged order, as on the outside of the colosseum (AD 72-82). With the ever-increasing use of concrete in the structure of buildings, the orders, originally structural, were gradually relegated to a purely decorative function.
Local materials, techniques, and building forms more or less dominated architecture in the provinces. The eastern Mediterranean continued in the established local and Greek Hellenistic building conventions, but imperial Rome succeeded in exporting to the East such building types as monumental baths, aqueducts, and, to some extent, amphitheaters, not previously found there.