Several major fires are documented in Ostia. A calendar, the Fasti, mentions a fire that started on January 1st, 115 AD in a vicus ("neighbourhood"), of which the name has not been preserved: "several buildings burned down" (praedia complura deusta sunt). During the reign of Marcus Aurelius baths had to be restored that were "destroyed by the force of fire" (vi ignis consumptas). During the excavations traces of fire were noted repeatedly, for exemple in bakery Caseggiato dei Molini (I,III,1) that was reduced to ashes at the end of the third century.
The importance of Ostia and Portus for Rome necessitated a good protection against fire. From a few inscriptions can be deduced that Augustus had stationed the sixth Praetorian Cohort at Ostia. They assisted in fighting fires: one of the soldiers (his name is not known) died when fighting a fire, and was given a public funeral by the inhabitants of the city:
|
[---]VI MILITI COHOR(tis) VI PR(aetoriae) OSTIENSES LOCVM SEPVLT(urae) DEDERVNT PVBLICOQ(ue) FVNERE EFFERVN(dum) DECRERVNT QVOD IN INCENDIO RESTINGVENDO INTERI[t] IN F(ronte) P(edes) XII IN AG(ro) P(edes) XXV |
 |
| CIL XIV, 4494. Travertine. Found in 1912 in tomb B4 of the Porta Romana necropolis. Cébeillac-Gervasoni 2010, fig. 70.1. |
But this cohort returned to Rome by order of Tiberius. Seneca has recorded an anecdote from the situation that then arose: "In the reign of Tiberius Caesar the fire brigade hurried off to the relief of the colony at Ostia, supposing it to be in flames; during the greater part of the night there had been a dull glow in the sky, which appeared to proceed from a thick smoky fire".
For Claudius, during the work on Portus, Ostia gained more significance. "He stationed a cohort at Puteoli and one at Ostia, to guard against the danger of fires", says Suetonius. These were recalled to Rome, but possibly only temporarily, by Otho in 69 AD.
A stamp on a reused water-pipe from the reign of Domitian speaks of conduits leading to castra, which again suggests the presence of cohorts to fight fires. As wel shall see, the earliest phase of the Ostian Barracks of the Fire Brigade, the Caserma dei Vigili (II,V,1-2), can be dated to the reign of Domitian (81-96 AD).
In the second and third century detachments (vexillationes) from Rome, composed of vigiles from the seven cohorts, were stationed in the harbours. Part of the detachment was stationed in Ostia, the remainder in Portus. Each detachment stayed in the harbours for a period of four months, arriving on the Ides of April, August and December. Inscriptions suggest that they were made up of four centuriae. The centuries were composite, in the sense that men from different centuries in Rome were brought together in one century. The detachment was led by a tribune, the praepositus vexillationis, later by a subpraefectus. With a nominal size of 80 men per century, the total number of men would have been 320, after the doubling of the forces in 205 AD 640. A very rough estimate suggests that in Rome, with about half a million inhabitants, there was one fire-fighter for 64 inhabitants, in Ostia and Portus, with perhaps 25.000 + 10.000 inhabitants, one for 55 inhabitants.
In cities other than Rome, guilds were called upon to fight fires: textile dealers (centonarii), carpenters and masons (fabri), and guilds in the cult of the Magna Mater that apparently had expertise in wood (dendrophori). In the harbours the vigiles may have worked together with such guilds, especially the builders, fabri tignuarii, who were organized in a military way under a praefectus.