Insula Orientalis IIa traditionally and erroneously called " palestra ", constitutes the most important public monument known at Herculaneum. The study of the building techniques used allows an outline of its construction history. It was begun during the Augustan period and completed during the last decade of the reign of Tiberius. During this long period of construction, minor changes were made to the unified plan, which eventually resulted in the definition of a building with a double function, not only public and religious, but also private, both residential and commercial. During the forty or fifty years that it was used, this building underwent important changes. With the growth of private space at the expense of the public, many parts are rearranged, sometimes employing techniques that basically come down to " do it yourself " and improvisation. The two restoration campaigns (carried out after various seismic events), the second of which was financed by Vespasian, permitted the reestablishment of a more rational use of space, but the previous practices resumed again quickly afterwards. Through the example of Insula Orientalis IIa it is therefore possible to perceive the tension that forms between public and private uses within a publically owned architectural structure which is strongly modified, in both its partial function as well as its spatial configuration, by private usage.
