Insula (building) in the context of Conímbriga

The Latin word insula (lit. 'island'; pl.: insulae) was used in Roman cities to mean either a city block in a city plan (i.e. a building area surrounded by four streets) or later a type of apartment building that occupied such a city block specifically in Rome and nearby Ostia. The latter type of Insulae were known to be prone to fire and rife with disease.

A standard Roman city plan was based on a grid of orthogonal (laid out on right angles) streets. It was founded on ancient Greek city models, described by Hippodamus. It was used especially when new cities were established, e.g. in Roman coloniae.

In ancient Rome, the domus (pl.: domūs, genitive: domūs or domī) was the type of town house occupied by the upper classes and some wealthy freedmen during the Republican and Imperial eras. It was found in almost all the major cities throughout the Roman territories. The modern English word domestic comes from Latin domesticus, which is derived from the word domus. Along with a domus in the city, many of the richest families of ancient Rome also owned a separate country house known as a villa. Many chose to live primarily, or even exclusively, in their villas; these homes were generally much grander in scale and on larger acres of land due to more space outside the walled and fortified city.

The elite classes of Roman society constructed their residences with elaborate marble decorations, inlaid marble paneling, door jambs and columns, as well as expensive paintings and frescoes. Many poor and lower-middle-class Romans lived in crowded, dirty and mostly rundown rental apartments, known as insulae. These multi-level apartment blocks were built as high and tightly together as possible and held far less status and convenience than the private homes of the prosperous.

The Insula dell'Ara Coeli is one of the few surviving examples of an insula, the kind of apartment blocks where many Roman city dwellers resided. It was built during the 2nd century AD, and rediscovered under an old church when Benito Mussolini initiated a plan for massive urban renewal of Rome's historic Capitoline Hill neighbourhood.