Concrete and bricks

In 117 AD Trajan was succeeded by Hadrian. A quick glance at a map of Ostia showing the building activity during Hadrian's reign clarifies why Ostia is famous for this period. Pliny the Younger did not live to see the new developments: he died around 113 AD.

Map of Ostia with buildings from the reign of Hadrian (hatched).

The leading magistrates in Ostia were two duoviri, mayors, appointed for periods of one year. Hadrian was duovir twice, for the second time in 126 AD. The function may have been honorary: he held similar magistracies in many other cities, and other Emperors have been duovir of Ostia. But holding the office twice is significant. It put Hadrian in a position in which he was informed about any legal and financial problems, and could then intervene. When the work began, there were many Pompeian-style houses in Ostia: domus with an atrium, tablinum and peristylium. These were replaced by commercial premises with apartments on the upper floors. Selling the old houses may have been profitable, but not all owners may have given them up without a protest. The roads, including drainage and water pipes, needed an update.

Dated brick-stamps show that much of the new building activity took place in the first decade of Hadrian's reign. Concrete walls, often 60 centimetres thick, formed the skeleton of high-rising buildings. The walls were faced with bricks or a combination of bricks and small tufa cubes. The archaeologists speak of opus latericium and opus mixtum, brick work and mixed work. As a rule the facing was of astonishing quality: smooth and regular. It suggests that the facades of many buildings were initially not covered with a layer of white plaster. It is mainly these skeletons that the modern visitor sees: sometimes with older buildings in between, often with later modifications and additions.

Confusing remains of different phases at different levels. Photo: Klaus Heese.

The builders of Ostia were called fabri tignuarii, carpenters. The jurist Gaius gives a definition:

Fabros tignarios dicimus non eos dumtaxat, qui tigna dolarent, sed omnes qui aedificarent.	We do not describe as carpenters only those who cut wood but everyone who is a builder.
Digesta 50.16.235.1. Translation Alan Watson.

The guild seat of the builders, the House of the Triclinia, was built during the reign of Hadrian and located next to the forum, a clear indication of their importance. The guild is documented in some 55 inscriptions. The builders were organized in a military way, led by a praefectus, and divided into sections of 22 members headed by decurions (not to be confused with the members of the city council of the same name). Presumably they also assisted the fire-brigade (vigiles).

Fabri tignuarii at work. A painting from the burial chamber of Trebius Justus in Rome, from the fourth century AD.