When is a siege not a siege?

Archaeology is full of mysteries. The best we can expect of scholars is that they set aside personal prejudice and weigh up the available evidence, presenting it in a way that permits logical analysis. But there is a major caveat in this last phrase, because it’s the contemporary logic that we must apply, not our preferred twenty-first-century logic. And this is where the sheep diverge from the goats.

Fifteen years ago, I devoted a whole series of articles in the magazine Ancient Warfare to this very phenomenon. The series was entitled “The Debate”, because each article presented the available evidence to illuminate a particular topic, and assessed the ongoing debate about how that evidence should be analyzed.

For “The Debate” in December 2011 (in Ancient Warfare vol. V, issue 6), I took as the theme the Roman military operations at Burnswark in south-west Scotland (known as Birrenswark in the older literature), where the upstanding remains of two camps are imprinted on the landscape.

The article (available here) was called “Hillfort under attack: Roman siege warfare or training exercises at Burnswark?”, because these were the two explanations that had been put forward in the ongoing debate. (I say “ongoing debate”, but it has always been a little one-sided, as proponents of the “training exercises” theory insist that all evidence favours their case.)

From antiquarians to archaeologists

Over a century ago, in 1914, Francis Haverfield, the pre-eminent Romano-British archaeologist of his day, had voiced the opinion that “the well-known and remarkable earthworks at Birrenswark have long been explained as Roman siege-works round a native hill-fort” (though he failed to name those authorities by whom it had “long been explained”).

A year earlier, the site had been visited by the German archaeologist Adolf Schulten, who — fresh from his eight seasons of excavations at the elaborate Roman Republican siegeworks of Numantia (see here) — immediately confirmed Burnswark as the site of a Roman siege. (It should be mentioned, however, that it was his belief in a circumvallation, disproved soon afterwards, that prompted his analogy with Caesar’s siege of Corfinium in 49BC, a comparison that is still occasionally mentioned to this day.)

Only a decade later, Haverfield’s pupil R.G. Collingwood, investigating the site in 1925, confirmed that “the siege theory gives the only possible explanation of the camps and their relation to the hill-fort”.

In the swinging sixties, anything goes

Then, at some point in the 1960s, the peculiar idea took root — popularized by Roy Davies in a 1972 paper entitled “The Romans at Burnswark” — that the only siege at Burnswark had actually been a practice siege!

When I was researching my PhD in 2001, I identified a lecture delivered in 1963 by Kenneth Steer (Secretary General of the Royal Commission on the Ancient and Historical Monuments of Scotland) as the first time this idea was mentioned. “It is at least arguable”, Steer pronounced, “that the camps were simply training-quarters for troops engaged in storming native fortifications”.

Indeed, Roy Davies’ PhD thesis (entitled Peace-time routine in the Roman army, Durham 1967) — for which he began research in 1963, the very year of Steer’s lecture — has a chapter on “Manoeuvres”, in which he admitted that “the theory that Burnswark may not in fact be the scene of a siege carried out in time of war was suggested to me by Mr G. Jobey”, an archaeology lecturer at Newcastle University who had been excavating there in 1965 and 1966.

For the next forty years, the “practice siege” theory held sway, despite the fact that — unlike other Roman army manoeuvres — there was not a single jot of evidence to support the existence of such a thing.

For example, Gordon Maxwell gave it prominence in his 1998 book A Gathering of Eagles, from which this illustration (right) is taken. Here we see the north rampart of the South Camp, where the author has depicted catapults mounted on mounds in the open area outside the camp.

Siege or no siege?

In 2003, I published a paper — “The Roman Siege of Burnswark” (available here) — in which I restated the case for a genuine episode of warfare. I rather foolishly imagined that this might have put the entire matter to bed. But I hadn’t reckoned with the argumentative energy of those who had set their minds and staked their reputations on the “practice siege” theory.

That is not to say that my research went unheeded. In 2009, for example, Nick Hodgson appealed to “the convincing demonstration by D. Campbell that there is no reason to believe that the siegeworks at Burnswark were not intended to function in earnest”.

But while the “training exercises” proponents insist on having the last word, I find their dogmatic belief in a “practice siege” curious. Even if we suppose for a moment that such a phenomenon ever existed, how would we tell it apart from a genuine siege?

A misconceived argument

Whenever anyone claims support for the “practice” theory, discussion always comes back to the “Three Brethren”. These are the earthworks positioned in front of the three north-facing gateways of the South Camp (depicted on the plan above).

In 1925, Collingwood pronounced them “emplacements for artillery bombarding the hill-fort”, which he (erroneously) called ballistaria. These were a particular hobby-horse of Collingwood’s, an obsession that he bequeathed to his student and collaborator, Ian Richmond. They were keen to find such “gun-platforms” in any camp or fort that they happened to be investigating. (I disproved five of them in a 1984 paper.)

The “Three Brethren” struck Collingwood as particularly suitable for this function, as his 20th-century logic told him that artillery should be thrust forward and elevated as far as possible. But to a Roman, neither of these characteristics appears to have been at all desirable.

Advancing artillery beyond the safety of the camp was foolish and reckless, while elevating it above ground-level was only necessary if its purpose was to shoot at the parapet of high fortifications. We can see this from the ancient technical manuals. Any self-respecting Roman engineer would have constructed a siege-tower for this purpose. But in the case of Burnswark, we may add the clinching fact that the “Three Brethren” are too small and precarious to be used as “gun-platforms”.

Maxwell’s illustrations (above and right) cleverly show a solid mound, carefully constructed from layers of turf, with a large consolidated surface area to support his catapult with a crew of four or five men. In reality, the mounds appear, on the contrary, to have consisted of piled up earth measuring some 10–12 feet (3.5m) in diameter at the top, which is a tight fit for a 2-pounder ballista, with no spare room for the crew to work effectively. (How did they even get the catapult up there to begin with?) In the case of this one-armed onager, it is unclear how the rear of the machine would be supported, far less operated.

Back in 2003, I gave a talk to the Trimontium Trust in Melrose on this subject, in which I plotted the trajectory of a missile from a 2-pounder Roman stone-throwing catapult located safely behind the rampart of the South Camp, where it ought to be. I demonstrated that the hillfort of Burnswark was well within the range of such machines, without having to position them precariously on mounds dangerously exposed outside the Roman defences.

The cross-section view of the terrain at Burnswark also demonstrates very clearly the danger posed to the Roman camp by an enemy located on the hilltop. The gateways were especially exposed, in this regard, and required robust protection. In fact, we know of a genuine Roman description of such robust defences being employed to deflect heavy and destructive objects rolled downhill against Roman fortifications. There is even an illustration of this on Trajan’s Column.

But the “training exercise” proponents object on principle to any contrary argument. David Breeze cannot disprove my interpretation of the “Three Brethren”, so he simply asserts that “this, of course, is based on the assumption that Burnswark was the location of a siege”. Thus, any suggestions may be swept aside on the grounds that Burnswark is a “practice siege” — a classic case of circular reasoning. Alan Wilkins likewise claims that “the design of the Three Brethren and their position immediately in front of the three gateways is the most important evidence that this is not a real siege”. For him, the catapult balls and copious quantities of sling bullets are “the types of missiles that might be expected at a training camp”. There is no replying to this level of debate.

How rumours start

In 2011, Rebecca Jones published a book entitled Roman Camps in Scotland. I recently acquired a copy (thank you, Ruth and Ruairi) and was surprised by her discussion of Burnswark (pages 154–156). It wasn’t her characterisation of the “practice siege” theory as the most likely interpretation, as I fully expected this. Rather, it was her allegation — in the context of the “Three Brethren” — that “he [meaning me] has accepted the possibility that they are ‘ballistaria’!

This is quite impossible, for two reasons. First, I have never wavered in my scepticism of Collingwood and Richmond’s “gun-platforms”. Over forty years ago, I demonstrated that the variety of archaeological features that they wished to identify as “artillery platforms” were no such thing. The “Three Brethren” fall into this same category.

And second, more importantly, in my 2003 book on Greek and Roman Artillery 399 BC–AD 363, I explained the meaning of the word ballistarium: “for a long time scholars interpreted this as an ‘artillery platform’, but it was probably a storehouse or workshop for catapults”. So, definitely not a large pile of earth defending a camp gateway!