Capitolium and Thermae Maritimae

Hadrian created a clearly defined forum, dominated by a Capitolium, temple of Jupiter, Juno and Minerva. The impressive ruins have always been visible, a romantic marker of the location of the city, but unfortunately also a pointer for plunderers who burned Ostia's marble in lime kilns. The Capitolium was a white building, but only countless holes in which marble slabs were fastened testify to the decoration.

Walking towards the Capitolium. Photo: Daniel González Acuña.

The construction of baths by Hadrian, completed by his adoptive son Antoninus Pius, is documented in an inscription in the Galleria Lapidaria of the Vatican Museums:

IMP(erator) CAESAR DIVI HADRIANI FIL(ius) DIVI TRAIANI PARTHICI NEP(os) DIVI [Nervae] PRONEPOS T(itus) AELIVS HADRIANVS ANTONINVS AVG(ustus) PIVS PONTIF(ex) MAX(imus) TRIB(unicia) POTES[tat(e) II co(n)s(ul) II?] THERMAS IN QUARVM EXSTRVCTIONEM DIVOS PATER SVVS ((sestertios)) XX ((centena milia)) POLLI[citus erat] ADIECTA PECVNIA QVANTA AMPLIVS DESIDERABATVR ITEM MARMORIBVS AD OMNEM C[ultum fecit?]

The Emperor Caesar, son of the deified Hadrian, grandson of Trajanus Parthicus and great-grandson of the deified Nerva, Titus Aelius Hadrianus Antoninus Augustus, pontifex maximus, wth the tribunicia potestas for the second time, consul for the second time, delivered the baths for the construction of which his divine father had promised 2,000,000 sesterces, after adding more money than was wished for and also marble for the entire decoration.

Inscription recording the building by Hadrian and completion by Antoninus Pius of baths. Vatican Museums, Galleria Lapidaria. Late December 138 or 139 AD. Original length c. 3.60 m. CIL XIV, 98; EDR094043; EDCS-05700098; HD032542. Photo: Turci 2019, fig. 10.

For a long time it was generally assumed that the inscription comes from the Baths of Neptune, in the north-east part of Ostia. It is true that these were built during the reign of Hadrian and were most likely financed by the Emperor, in view of their size and location in the city.

Tourists admiring the mosaics in the Baths of Neptune from a platform. Photo: Klaus Heese.

However, after groundbreaking work by Marcello Turci, who re-examined the confusing old accounts of digging in the city, we now know that the inscription must have come from the Baths of the Marine Gate near the ancient beach. It was found amongst the ruins by the antiquarian Gavin Hamilton at the end of the 18th century. Brick stamps from the latter building coincide with a late Hadrianic date and an inauguration in the first months of the reign of Antoninus Pius, in December 138 or 139 AD. The name of these baths is known from an inscription from the late 4th century: Thermae Maritimae, Maritime Baths.

General view of the Baths of the Marine Gate, from the south-east. Photo: Massimiliano David.

Ostia would always be a functional port, without marble colonnades, with only a modest display of wealth. But by reorganising the forum and donating baths, Hadrian added elements of pleasure and civic pride. Today visitors can admire the black-and-white mosaics in the baths. A keen eye will spot remnants of marble decoration. What is blatantly missing however are the statues that were once placed in countless niches: these were taken to museums.