Insulae

In Roman architecture, an insula (Latin for "island," plural insulae) was a kind of apartment building that housed most of the urban citizen population of ancient Rome, including ordinary people of lower- or middle-class status (the plebs) and all but the wealthiest from the upper-middle class (the equites). The term was also used to mean a city block.

The traditional elite and the very wealthy lived in a domus, a large single-family residence, but the two kinds of housing were intermingled in the city and not segregated into separate neighborhoods. The ground-level floor of the insula was used for tabernae, shops and businesses, with the living space upstairs. Like modern apartment buildings, an insula might have a name, usually referring to the owner of the building.

Strabo notes that insulae, like domus, had running water and sanitation. But this kind of housing was sometimes constructed at minimal expense for speculative purposes, resulting in insulae of poor construction. They were built in timber, mud brick, and later primitive concrete, and were prone to fire and collapse, as described by Juvenal, whose satiric purpose in writing should be taken into account. Among his many business interests, Marcus Licinius Crassus speculated in real estate and owned numerous insulae in the city. When one collapsed from poor construction, Cicero purportedly stated that Crassus was happy that he could charge higher rents for a new building than the collapsed one.

Living quarters were typically smallest in the building's uppermost floors, with the largest and most expensive apartments being located on the bottom floors. The insulae could be up to six or seven stories high, and despite height restrictions in the Imperial era, a few reached eight or nine stories. The notably large Insula Felicles or Felicula was located near the Flaminian Circus in Regio IX; the early Christian writer Tertullian condemns the hubris of multiple-story buildings by comparing the Felicles to the towering homes of the gods. A single insula could accommodate over 40 people in only 3,600 sq ft (330 m²); however, the entire structure usually had about 6 to 7 apartments, each had about 1000 sq ft (92 sq m)

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