The importance of Puteoli as harbour of Rome implies that there must have been many warehouses in the city. In 1971 Geoffrey Rickman, in his general study of Roman warehouses, wrote: "The importance of Puteoli in the late Republic and early Empire is well known, but so far no excavation has disclosed evidence for its warehouses and their distribution around the harbour. Recently there was a reference in an Italian newspaper (Il Tempo, 18 February 1961) to the discovery there of five connected storerooms for grain, but no details are discoverable. The only other possible source for the disposition and appearance of horrea at Puteoli might be the antique picture found on the Esquiline. The latest attempt to identify its location has favoured Puteoli. On it is depicted a building labelled HORREA."

The warehouses are referred to by Cicero as a particularly valuable asset:

Num igitur utiliorem tibi hunc Triarium putas esse posse quam si tua sint Puteolis granaria?	Well, but surely you don't reckon Triarius here a more valuable asset than the granaries at Puteoli would be if they belonged to you?
Cicero, De finibus bonorum et malorum II,26,84-85. Translation H. Rackham.

Today we know a lot more about the warehouses of Puteoli, first of all through the discovery and decipherment of the archive of the Sulpicii. Two warehouses feature in the contracts. The Horrea Barbatiana were owned by Domitia Lepida, an aunt of Nero. She had been married to M. Valerius Messala Barbatus, who gave his name to the warehouse and passed them on by inheritance. The Horrea Bassiana were owned by the city of Puteoli (horrea publica Puteolanorum). They may have been donated to the city by a Bassus, further unknown.

We learn that the warehouses, horrea, had subdivisions like horreum XII, horreum XVI. Each warehouse had components: horrea ima, media and superiora, the lowest, middle and highest warehouse. Perhaps the different levels were related to a natural inclination of the terrain. The contracts are agreements about the renting of parts of a warehouse, where grain from Egypt and vegetables were stored. Egypt was, together with Tunisia, a main supplier of grain for the Imperial distributions in Rome, but this Egyptian grain was not meant for the frumentationes. The transactions in the archive document the private business of merchants, bankers and caretakers of warehouses. The stored commodities served as collateral for financial loans. Slaves, freed slaves and free people were involved.

C(aio) Caesare Germanico Augusto Ti(berio) Claudio Nerone Germanico co(n)s(ulibus) sextum nonas iulias. Diognetus C(aii) Novi Cypaeri servus scripsi iussu Cypaeri domini mei coram ipso me locasse Hesycho Ti(berii) Iuli Augusti l(iberti) Eueni ser(vo) horreum duodecimum in horreis Bassianis publicis Puteolanorum mediis in quo repositum est triticum Alexandrinum quod pignori accepit hac die a C(aio) Novio Euno item in iisdem horreis imis inter columnia ubi repositos habet saccos leguminum ducentos quos pignori accepit ab eodem Euno. Ex k(alendis) Iuliis in menses singulos sestertiis singulis num(mis). Act(um) Put(eolis)

Under the consuls Gaius Caesar Germanicus Augustus and Tiberius Claudius Nero Germanicus on the 6th day before the Nones of July. I, Diognetus, slave of Gaius Novius Cypaerus, have written by order of my master Cypaerus and in his presence that I let to Hesychus, slave of Tiberius Iulius Evenus, freedman of Augustus, horreum XII in the middle public Horrea Bassiana of the Puteolans, in which is stored Alexandrian grain, which as a guarantee he receives today from Gaius Novius Eunus, likewise in the same lower horrea between the columns, where he stores two hundred sacks of vegetables, which he receives as a guarantee from the same Eunus. From the Kalends of July in each month one sesterce. Transacted at Puteoli.

TPSulp. 45 (EDR079328), dated 2 July 37 AD.

C(aio) Laecanio Basso Q(uinto) Terentio Culleone co(n)s(ulibus) III idus Martias Nardus P(ublii) Anni Seleuci servus scripsi coram et iussu P(ublii) Anni Seleuci domini mei quod is negaret se litteras scire me locasse C(aio) Sulpicio Fausto horreum XXVI quod est in praedis Domitiae Lepidae Barbatianis superioribus in quo repositum est tritici Alexandrini millia modium XIII quae dominus meus adme tietur cum servis suis mercede in mensibus singulis sestertis centenis nummis Act(um) Puteolis

Under the consuls Gaius Laecanius Bassus and Quintus Terentius Culleo on the 3rd day before the Ides of March. I, Nardus, slave of Publius Annius Seleucus, have written in his presence and by order of my master Publius Annius Seleucus, because he says he is illiterate, that I let to Gaius Sulpicius Faustus horreum XXVI, which is in the estates of Domitia Lepida, in the upper Barbatiana, in which are stored of Alexandrian grain 13.000 modii, which my master will measure out with his slaves, for a rent in each month of one hundred sesterces. Transacted at Puteoli.

TPSulp. 46 (EDR075472), dated 13 March 40 AD.

TPSulp. 51 (EDR076977), dated 18 June 37 AD. Photo: Camodeca 2018, p. 190.

A few remains in Pozzuoli are regarded as possible horrea. In 1978 Paolo Sommella listed three locations, belonging to the first and second century AD (nr. 3, locality Pondera; nr. 17, Via Pergolesi; nr. 21, Palazzo SIP). Rows of a few rooms have been preserved, covered by barrel vaults.

Sommella, interior of locations 3 and 21. Photos: Sommella 1978, p. 18 and p. 38.

More recently Camodeca and his collaborators have recognized a warehouse in the submerged vicus Lartidianus, seen on the plan below. Room A is a courtyard with a porticus of brick semi-columns and pilasters, measuring 16 x 11 meters. It is paved with sesquipedales. In a corner is a large basin. Room B was also a courtyard. To the north and south are long rows of rooms (C, D). There seems to have been a further courtyard to the east (E), to the south of which are some deep rooms (G).

Plan of the structures in the vicus Lartidianus. Image: Camodeca et al. 2001.

We are here entering the area of the submerged harbour Portus Iulius, a short-lived military harbour from the first century BC, soon to be replaced by Misenum. This area may later also have played a role in commerce, and warehouses could be looked for here as well.