A short distance from the theatre is the monumental complex, erected during the Giulio-Claudia era in honour of Emperor Augustus. However, its current form dates back to the arrangements of the Antonine age (mid 2nd century AD), made by Cassia Victoria in honour of her husband L. Laecanius Primitivus, an Augustal priest of the time of Marcus Aurelius. Unfortunately, the structure was destroyed at the end of the 2nd century BC, most likely as a result of seismic events. When it was uncovered in 1967, several statues of Vespasian, Nerva, Titus, Abundance, and a number of deities were discovered, including Asclepius, Apollo and Venus, one of the Small Herculaneum type and another on a dolphin, which are now exhibited in the special room dedicated to the monument in the Archaeological Museum of the Phlegraean Fields. Half-submerged by bradyseism, the sanctuary consists of three adjoining rooms, partly built of masonry and partly carved out of the rock, which forms its side and back walls. The central building, the actual sacellum, consists of a rectangular temple with a podium in front of which is the altar. Via a marble staircase, lined by two masonry podiums, originally covered with marble slabs and overlooked by statues, it is possible to access the square pronaos with cipolin columns with parchment-type capitals, on top of the epistyle of which, bearing the inscription of dedication, was the pediment decorated with reliefs. After passing through the vestibule, which has a mosaic floor with a white-tiled carpet and black tiles, and crossing the marble threshold, the sacellum is entered. This is built of opus reticulatum with tufa walling, while its walls were covered with marble slabs. On the back wall is an apse with a podium, flanked by two rectangular niches, plastered and painted red on the upper part of the front, while it has a stucco decoration in the basin with reliefs of a marine subject. The floor is in cocciopesto with white tiles arranged to form squares and a central band in polychrome marble repeating the same geometric motif. The room to the right of the sacellum, built in opus reticulatum, was decorated with stucco cladding and painted plaster on the walls and on the barrel and cross vault. In the room on the left, on the other hand, a bronze equestrian statue of Nerva (originally Domitian) was found, now in the Archaeological Museum of the Phlegraean Fields.
