Welcome to my Monday Musings!
I've taken some time off my writing in progress to jot down some of my research on the fabulous Legionary Fortress at Inchtuthil in Perthshire, Scotland. This blog post is also intended for the shared blog posts associated with the Historical Writers' Forum where you'll find a huge range of eras and subjects covered by the group of historical authors that I'm delighted to be a part of.
Inchtuthil - Pinnata Castra, The Fortress on the Wing!
Mapmaking details of Claudius
Ptolemaeus (Ptolemy), writing around A.D. 120-150, name an Ancient Roman Fortress in
No large legionary fortress has ever been identified near the Moray Coast
It, therefore, makes sense that the huge fortress (21
ha/50+ acres) positively identified at a site named Inchtuthil in Perthshire was the one Ptolemy
calls Pinnata Castra since it’s the only large legionary-sized fortress ever identified in northern
Caledonia. Or it may be that Victoria was built further north at the Inchtuthil location and mistakenly plotted on the map! I chose to name Inchtuthil as Pinnata Castra in my Celtic Fervour Saga series since I like the idea of the fortress being on the wing, essentially at the edge of the fortifications that were built north of the Forth/ Clyde line.
At Inchtuthil there's evidence
of a legionary fortress likely to have been mainly built and garrisoned by the Twentieth
Legion (Legio XX Valeria Victrix). Built
to garrison as many as 6000 men (a full legion plus additional specialist troops),
its position was highly strategic and placed on a natural plateau with outstanding
views over the surrounding countryside. On the north bank of the River Tay, it
had access to sufficient water supplies and it was in the best place to monitor
one of the main natural routes into the Caledonian province of Britannia
The operations of the small vessels
of Agricola’s Roman Navy were crucial elements in the success of the Caledonian
campaigns. It’s likely that only smaller vessels of Agricola's fleet could have navigated
up the River Tay but they would have played a regular role in supplying the
north of Caledonia . It's always worth mentioning that Agricola was innovative in
using his Classis Britannica (Roman Navy) for more than in a supply role – he
also appears to have given the fully armoured mariners an aggressive role in
subduing the natives who lived close to the eastern coastline of Northern Britannia. This seems to account for the fact that coastal forts or fortlets in north-east Caledonia are quite rare.
Though the only legionary fortress in northern Caledonia, Inchtuthil was part of a line of strategic defence structures intended to control movement of the natives between the highlands and the fertile plains of current-day
South of the
Gask Ridge, Agricola also had sufficient defences controlling the Forth/ Clyde line which effectively monitored the southern accesses
to the highlands.
The fortress at Inchtuthil was the lynchpin of all of these highland defences.
Agricola’s aim was probably to use this fortress as a supply base for all future operations north of the Central Belt of Scotland, there being many tribes and
territory still to subdue in the far north.
Since the site of the fortress
was never built over in ensuing centuries after the Roman occupation, and
remained pastureland, it allowed for thorough archaeological excavation (Richmond
1952-1965), though some small-scale investigation of the site had been
undertaken in the very early 20th century. Because of its location and undisturbed
condition, Inchtuthil is the only site across the Roman
Empire that provides the best complete plan of a legionary
fortress.
Inchtuthil’s main barrack accommodation
blocks (64) were built close to the perimeter but behind the intervallum – the space left free inside
the rampart walls the distance of it being set to be the widest extent that
missiles from outside the walls could fall. The intervallum space was probably also used for mustering and rapid deployment
of troops, and used regularly for drills. Larger than normal workshops (N) were
created for manufacturing all of the iron requirements needed for a permanent
stay in northern Caledonia (for tools, weapons, and fort building components
like nails and brackets). A very sizeable hospital was also built. An outside
rectangle of small rooms faced a smaller rectangle of rooms, the rows separated
by a walkway (K). To the interior lay an open courtyard.
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| courtesy of SCRAN/ RCahMS |
The timber walls of the above
buildings alone had an approximate perimeter of 7 miles so the wood cut to
create the whole fort would have denuded forests for miles all around the area.
It’s estimated that building such a large installation would have taken a few
years, the troops living in tented accommodation in the temporary camps
situated outside the fortress till the barrack buildings were completed.
There seems to have been construction priorities at Inchtuthil. Some of the expected buildings were never completed
and others were unexpectedly small. Generally in a fortress of this size there
would have been a sizeable headquarters administration block (P - principia) and a generously-sized
building to quarter the legionary commander (praetorium) built in the centre of the fortress behind the via principalis – the main road that ran
transverse between slightly offset side gate entrances. At Inchtuthil, there is
an unusually small principia and no
evidence that a praetorium was ever
constructed on the empty space that was laid out for it. This meant a fairly
empty centre to the fortress. And some of the Tribune's officer accommodation wasn't completed.
There's evidence for 5 massive granaries, designed to hold months, perhaps even years, worth of grain. It's possible their size was designed to accommodate grain 'payments' from the locals - although there wasn't really all that much fertile soil for grain crops in north-east Scotland. The locals mostly grew oats and barley, the latter being a ration apparently hated by the Roman troops. It's possible that space for a further 6th granary was laid out but not used. Agricola's concept of Inchtuthil being a huge supply fortress for an offensive further north at some future date was sound, especially in the amount of food stocks that were necessary to feed his four Britannic legions spread throughout the whole island of Britannia. The general troop diet was mainly a wheat-based one - bread and a form of brose/ porridge, and hard tack biscuits when on campaign - but it took tons of grain to feed those men.
The small principia functioned as the headquarters
building, the records store, the place where justice was meted out and where
religious ceremonies took place. The aedes - the rear section - would have housed the precious emblems and standards of the legion, the emperor’s image, and altars for
worship with the strong room beneath for storage of the legion pay-chests.
There may have been a plan for this building to have been enlarged at some
point but that never happened. Outside the fortress walls there was a temporary camp officers' compound which seems to have been used during most of the construction phase. It may be that the principia was small because official business was still being conducted from the officers' compound. Interestingly, the remains of a small personal bathhouse were found near that senior staff compound.
General Agricola was recalled back to Rome in early A.D. 85 but it's not clear who his successor was. It may have been G. Sallustius Lucullus [executed in A.D 94 and there's a nice story for this for another post] but, if him, his tenure as Governor of Britannia would have been incredibly long. By the time Agricola was recalled to Rome, and his almost unparalleled 7-year tenure ended, Emperor Domitian had already been withdrawing troops from Britannia for some years. Caledonia was seriously undermanned when Agricola left and the troops stretched too thinly across the island of Britain to maintain control over all of the areas invaded. Inchtuthil may have been Agricola's 'pet project', built for sound reasons when in aggressive invasion mode but Agricola's successor may not have had the authority from Domitian to continue to man the northern areas of Caledonia, or even the will to continue with Agricola's ambitious plans. It's not clear when all of the troops retreated from the north and were deployed in southern Britannia after Agricola left Caledonia, but most historians think the troops withdrew down to around Trimontium (Melrose on the Scottish Borders) by the late A.D. 80s.
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| General Agricola- Wikimedia Commons |
The fortress at Inchtuthil was
probably dismantled and evacuated around A.D. 87 (coin evidence indicates before A.D. 90), the
likeliest reason being that Emperor Domitian needed more troops because he was heavily involved in war in
Moesia (Balkans)/ and Dacia . Domitian recalled troops of the Legio II Adiutrix Pia Fidelis from
Britannia to stem the unrest.
This left the northern areas of Caledonia
undermanned. It's thought that most of the troops of the Legio
XX moved south to man the base at Deva Victrix (Chester
The dismantling process at
Inchtuthil was an organised one. If there were elements in the fortress that
could be used elsewhere in Britannia, or even across the wider Roman Empire , they would have been packed up and carted
off during the withdrawal. Items unwanted like already chipped pottery, unrepaired
fittings tended to be consigned to the rubbish pits. In general, nothing was
left that the enemy could use to their advantage. Since iron seems to have been
the most prized commodity in Late Iron-Age society in Caledonia ,
probably even more esteemed than gold or silver, it is highly unusual that a
massive amount of iron was left at Inchtuthil. Naturally the iron stocks weren’t
just left lying around!
Since the workshops were up and producing early in its
history, it’s thought that there were huge stocks of nails ready and waiting
for major fort building further north, the Caledonian campaigns expected to continue
for some time. Nails of varying sizes, from very small to the huge spikes that
were used to connect thick upright posts, were purposely packed into a deep pit
and covered over before the fortress buildings were set alight prior to the
evacuation of Inchtuthil, a normal procedure when abandoning a fortress. It seems
as though the almost one million nails (875,400), iron wheel rims and fittings - upwards of 10 tons worth - were impossible to cart away and this was an attempt to deny the locals from finding
them and melting them down to make valuable weapons.
When Richmond
I’m currently writing about this
amazing fortress in Book 5 of my Celtic Fervour Saga series. My character Agricola
has been summoned back to Rome Caledonia .
Happy Reading.
Slainthe!
