As a fire investigator for the London Fire Brigade, David Townsend covers all of western London, responding to all large fires, all fires that result in serious injuries or fatalities, and any fire where the fire officer in charge is not able to determine the cause. Aiding in the research for “The Great Fire Of Rome,” Townsend supervised a re-creation of how Rome’s fire may have spread from the wooden tenements of the city’s slums to the more solid stone structures in which the aristocracy lived. Previously, Townsend has lent his expertise to mock-ups of the great 1666 fire in London.
Townsend’s reconstruction of the Roman fire of 64 A.D. took place in a fire chamber, where a simulation of a Roman aristocrat’s home was ignited to see how “a full-sized room with two beds, or lounges, and some other various furnishings and wall hangings” would burn. “The initiation source of the fire was assumed to be an ember entering from a window to reconstruct a fire that spread to that room from an external fire source,” Townsend says. “Timber kindling was set behind one of the lounges, and that was lit remotely by a naked flame and we just watched it go.”
Those who see “The Great Fire Of Rome” episode will notice that the replica home featured in the experiment only has three walls. “When these reconstructions are made,” Townsend explains, “one side of the room is missing completely to facilitate filming. It’s just not possible otherwise. In essence, that means the room is fully ventilated during all stages of the fire, which, for the Rome fire, I suspect, would not take away from any of the realism. Because I suspect there were quite open [housing] developments [in ancient Rome] anyway.”In his attempts to blame the emperor Nero for the fire, the Roman historian Tacitus stated that it could not have naturally spread from the timber-framed tenement buildings of the slums to the stone houses around the Forum in which the senators lived, and that the only explanation for the destruction of these sturdier stone dwellings was arson. Townsend suggests that these houses weren’t as impenetrable as Tacitus may have thought. “The decorative masonry is the type that would be used to cover the construction — much of the construction in buildings is not attractive, and this would be the sort of masonry you’d use to sort of cover those elements of construction. And that would create voids in a building, which, if the material covering was breached, could easily spread the fire.” Indeed, during the simulation, a large portion of this masonry collapsed under the force of the fire.
Moreover, if, by the time it reached the Forum, the fire had escalated to the strength of a firestorm, the aid of an arsonist would have been most unnecessary. “That’s a phenomenon that happens in large fires, during the war years in particular, where there is such a great amount of fire that the whole city, or a large area of the city, becomes one … what we call conflagration. And in a large fire, it can create its own weather system. It draws in fresh air at the base to replace all that that it is sending up into the sky. And that wind rushing in can be pretty forceful. When there’s a large conflagration, the wind direction is coming from everywhere. So what’s happening in the center, you get some spectacular swirls and vortexes in a firestorm. Once a fire gets going in a large area, in a large town or city area, when you’re talking about a conflagration and when firestorms become relevant, then the size of the house is not relevant. A big house is rendered very insignificant in a big fire. It’s a big equalizer, fire.”
Tacitus also suggested that the second stage of the fire, which burned for six days before being contained, only to rekindle and burn for another three, could have been due to foul play. To Townsend, this aspect of the fire’s behavior is merely normal. “Smoldering embers can remain on the scene for a good period of time — many, many hours — particularly if it’s in a remote place, not many people around it. So a fire can be thought to be extinguished, but in fact rekindle many hours later.”
Today, the chance of a fire rekindling is slim due to the experience of professional firefighters and the sophistication of their techniques. “It’s something that’s more akin these days, in modern firefighting, to forest fires,” Townsend says. Yet in Roman times, such an occurrence would have been very likely. “The area of damage is so great, and the primary firefighting method would be creating firebreaks — pulling buildings down in front of the fire. Then it’s more likely that rekindlings will occur. And also in such places where there is any kind of civil unrest going on, which I understand there may have been — or some element of crime — then there is the deliberate resetting of fires that’s going to be a possibility.”
Regrettably, identifying an arsonist 2,000 years later is virtually impossible. “To investigate such a thing … it would be difficult to prove. You’d need very credible witness evidence to prove such a thing.” It seems likely, then, that the mystery of exactly who or what caused the great fire of Rome will remain unsolved for at least another 2,000 years.