Roman sanctuaries

A sanctuary was a sacred precinct, not a single temple: an altar, a small shrine for the god, and the porticoes, terraces and stairways around them. The Shrine of Hercules Curinus above Sulmona was enlarged into a large terraced sanctuary after the end of the Social War in 89 BC, and it.wikipedia compares it with the sanctuary of Fortuna Primigenia at Palestrina and that of Hercules Victor at Tivoli, built in the same period.

At Sulmona what survives is the frame rather than a standing temple: terrace walls, a stairway, the vaulted rooms of a podium. The best finds are in the Archaeological Museum in Chieti (it.wikipedia).

Sanctuaries also changed over time. The upper part of the Sulmona sanctuary was buried by an ancient landslide around the 2nd century AD, yet people kept coming: a church was later added beside the southern stairway (en.wikipedia). Its sacellum, the small shrine of the god, yielded two cult statues of Hercules, and a small column scratched with twelve lines of verse attributed to Ovid (it.wikipedia).