Petuaria Part III: A Lost Saxon Shore Fort?

The Saxon Shore
The first excavators of Brough on Humber, Philip Corder with Rev. Thomas Romans, who explored the site in the 1930s saw the site as a military or naval fortified base controlling the River Humber and access to York. Corder speculated that it may have been part of the chain of coastal defences known as the Saxon Shore forts. John Wacher carried out excavations at Brough between 1958-61 and found no evidence for a significant civilian settlement and agreed with Corder that it was a military site, which he also considered included a naval base which may well have been part of the Saxon Shore defences.

Wacher’s chronology for the settlement at Brough on Humber commences in the 1st century as an auxiliary fort that was abandoned around AD 80. However, he considered that during this period it was likely that a military supply depot was maintained there. In the later 3rd century the fort was reoccupied perhaps as an outlier of the Saxon Shore defensive chain, and then finally abandoned in the last quarter of the 4th century; the oldest coinage dating to the reign of the usurper Magnus Maximus (383-388).

Situated on a natural inlet of the river Humber, the military base at Brough would have fulfilled two functions: it controlled the approaches to the estuary linking to several major rivers that provided access to the heartland of Britannia; the same function was performed by the Saxon Shore forts at Brancaster on the Wash and Reculver on the Thames estuary.

Secondly, it functioned as a port serving the Roman forts at York and Lincoln and surrounding areas such as the fort at Malton. Brough also served as the northern terminal of the Humber crossing linking York and Lincoln by the Roman Road known as Ermine Street. However, it must be conceded that, to date, neither side of the crossing has produced evidence of a harbour. Wacher attributes this to the Late Roman marine transgression which would have submerged the existing structures. 

During the 4th-5th centuries AD this significant geological phenomenon resulted in several Romano-British sites on the Lincolnshire marshes being completely covered over by several metres of marine alluvium. For example, The Romano-British sites at Scupholme and Ingoldmells were found beneath more than three metres of alluvium.

The Roman Shore Forts
The so-called Saxon Shore is a series of Roman defences along the south and east coasts of Britain. It is mentioned in just one official document, the Notitia Dignitatum (Register of Dignitaries), thus the sole source for its existence.

The (unknown) compiler of the Notitia Dignitatum listed the official titles of all civil and military posts within the Roman Imperial administration around AD 395. The document consists of two sections, the Eastern Empire, and the Western Empire, revised and updated c.420. The western section lists the office of Comes litoris Saxonici per Britannias, the Count of the Saxon Shore for Britain, and is the only historical source for this otherwise unknown military command.

The Notitia records nine forts under the command of the Comes litoris Saxonici per Britannias forming a chain of coastal defences stretching from the Wash at the northern end and along the east and south coasts to the Solent; from Branodunum (Brancaster) in Norfolk to Portus Adurni (Portchester) in Hampshire and includes Othona (Bradwell), Dubris (Dover), Lemannis (Lympne), Gariannum (Burgh Castle), Regulbium (Reculver), Rutupiae (Richborough), and Anderida (Pevensey). To this list the Roman forts at Caister-on-sea (Norfolk) and Walton Castle (Suffolk) have been added by modern historians to make a total of eleven Saxon Shore forts. Could Petuaria (Brough on Humber) have been the twelfth?  

The forts are typically located on inlets or estuaries, all points of potential incursion into the Roman province. Large parts of the forts at Richborough, Reculver, Burgh Castle, and Bradwell-on-Sea have been lost to coastal erosion with Walton Castle now entirely submerged.

Walton Castle, near Felixstowe, is a unique case, now totally submerged under the sea owing to coastal erosion, however, old descriptions by antiquarians seem to confirm it was part of the chain of defences. The location and features make it almost certain that Walton Castle was a Roman Shore fort, being quadrangular in plan, with flint and mortar walls bonded with brick with round bastions. Strategically positioned to control access to the estuary of the Stour and Orwell. It is claimed that there are traces of a signal station system between Walton and Burgh Castles.

However, owing to a lack of positive evidence Walton Castle has not been universally accepted as a Shore Fort. The counter argument is that Walton was Portus Adurni rather than Portchester. Yet it is perfectly possible that by the time the Notitia Dignitatum was compiled the fort at Walton had been abandoned under reorganisations under Theodosius. 

Sentinels of the Waterways
Caister and Burgh Castle stood either side of the ‘Great Estuary’ controlling access in to the Broadlands rivers, (Yare, Bure and Waveney) behind Yarmouth, which was then a sandbank. Richborough and Reculver stood sentinel over the two ends of the Wantsum channel, a strait separating the Isle of Thanet from the north-eastern Kent, a major shipping route in Roman times. 

If, as seems likely, some of the Roman Shore forts were sited in pairs at main points of possible incursion to rivers or estuaries, as above, then we could expect to find another Roman port on the northern side of the Wash (Metaris Aestuarium), opposite Brancaster which guarded the southern side, perhaps near Skegness as the Roman road from Lincoln (Lindum) runs there. The 16th Century antiquarian John Leland makes reference to a ‘walled town’ and a ‘castle’ off the coast of Skegness. But any structures there were claimed by the sea long ago. 

‘Old Skegness’, as the local people refer to the Old Roman site, now lies about half a-mile off the coast after being swallowed by the sea in the 1500s following storms and floods. In addition to the clues mentioned by Leland of a lost Roman town or fort, sailors were still reporting encountering an old church steeple out there in the 17th century.

We could also expect to find a Shore fort guarding the Humber, such at Brough on Humber, and access into to York.

Dating the Forts
The Roman shore forts can be divided into two groups by age and design. The first group shows similarities in size and internal layout with most of the Roman forts in Britain.

The early group of forts comprises the two forts on the Norfolk coast, Brancaster and Caister, and Reculver in Kent. These forts are considered to have been constructed during the early 3rd century AD owing to their conventional architecture, the classic ‘playing card shape’, square sides with rounded corners, common in early Roman military architecture. Evidence from excavations supports the early date. In the days of early Roman Britain the forts were rarely attacked with the legions preferring to meet the enemy in the open field where their superior battle tactics and discipline proved dominant.

The second group, Burgh Castle, Bradwell, Reculver, Dover, Lympne, Pevensey, Portchester, were constructed during the late 3rd century. The principal differences between these later forts and the early group is the incorporation of new aspects of Roman fort architecture that originated in the east of the Empire to resist siege warfare against the Sassanids in the early 3rd century.

The addition of external bastions (turrets) provided the fort (or town wall) with additional defensive capability against an enemy directly attacking the face of the fort walls with battering rams or siege engines. With bastions external to the fort walls the attackers could now be subjected to artillery crossfire along the long axis of the wall.

Burgh Castle (Gariannonum) east wall bastion
(Creative Commons)

These novel features included the construction of thick walls (up to 3.5 m at Pevensey), bonded with brick courses, over 7m tall, whereas the earlier forts had thinner walls supported by earthen inner ramparts. The later forts all displayed variability of plan, from square as at Portchester, oval at Pevensey, to pentagonal at Lympne. Yet the signature features of these later forts is the external bastions on the fort walls. 

The majority of the external bastions incorporated into the Saxon Shore forts were circular, or semi-circular, solid masonry ‘drums’ as at Burgh Castle, Bradwell, Pevensey and Lympne. However, Portchester was constructed with hollow bastions which may indicate a shortage of building materials, it was not finished, or, being at the western end of the chain of Shore forts, was only considered likely to be suffer minor attacks.

The river wall and bastions completed the defensive circuit of Roman London, as with the later Saxon Shore forts and other fortifications in the north and west constructed at this time, all appear to have been built in a hurry.

Wacher considered that there was a close comparison between Brough on Humber (Petuaria?) and the Saxon Shore fort at Burgh Castle (Gariannum) in Norfolk. Wacher suggests that although the original plan at Burgh may have been pre-Carausian, that is before AD 286, the additional constructions including thicker walls, external bastions and towered gateways, were in place prior to the Theodosian restructuring following the Barbarian Conspiracy of AD 367. It is therefore likely that both forts were updated by Carausius, the usurper emperor (r.286-293) in the late 3rd century. He argues that the pattern of development at Brough is typical of the chronology of military fortification rather than civil settlement. 

Carausius
Marcus Aurelius Mausaeus Carausius, a Menapian of humble birth, was an officer in the Roman military service, a helmsman by profession. He had received recognition for fighting against the Bagaudae, groups of rebel peasants in the western parts of the later Roman Empire, who arose during the Crisis of the 3rd Century and persisted until the very end of the Western Empire.

Around 285-6 Carausius was appointed by Maximian, co-ruler with the emperor Diocletian, to deal with Franks and Saxon pirates who had ‘infested’ the Channel and were plundering the coast of northern Gaul. Carausius was given command of a fleet, or given authority to assemble his own, based at Gesoriacum or Bononia (Boulogne-sur-Mer) to counter the threat.

Carausius was remarkably successful but was accused of letting the pirates complete their raids, then attacking them to take their spoils for himself. Infuriated by this news Maximian ordered Carausius’s death. In 286, in response Carausius declared himself Emperor with the title of Augustus, over Britain and northern Gaul, issuing coins showing himself as co-emperor alongside Maximian and Diocletian.

Coin portraying Carausius alongside Diocletian and Maximian as joint emperors
‘CARAUSIUS ET FRATRES SUI’  (Carausius and his brothers!)

Several attempts by Maximian to remove Carausius failed, and in 290 he was finally acknowledged as ruler of Britain. On 1st March 293, Constantius was made caesar by Maximian. The two men, together with Diocletian and his caesar, Galerius, formed the 'tetrarchy'. Constantius was assigned to rule Gaul with his first instruction to remove the usurper Carausius. Shortly later he captured Carausius’s mainland base at Gesoriacum. Carausius pulled back to Britain but later that year was assassinated by his finance minister, Allectus. Three years later in 296 Allectus was killed in a battle with Asclepiodotus, the praetorian prefect, who landed on the south coast to recover Britain.

Brough on Humber: A Saxon Shore fort?
Although Wacher saw Brough on Humber as a naval base there has been no archaeological link established with the classis Britannica, the Roman fleet, probably constituted for the Claudian invasion in AD 43, but no longer documented after the mid-3rd century. Tiles marked ‘CLBR’ associated with the Roman fleet have never been found north of London.

However, if as seems likely that Carausius constructed the later Shore forts, and enhanced the defences of the earlier forts, he must have had an operational fleet. It is probably more correct to say that Carausius planned the Shore forts and they were completed by his successor Allectus. 

Other bases and Roman London were re-fortified at this time while new defensive shore forts were being established at Porchester while others at Brancaster and Lympne were being restored or repaired. At nearby Malton (Derventio), 23 coins of the Carausian period were found at the North-East gate of the fort during the 1927-30 excavations indicating it was probably rebuilt by Carausius. There was also significant reconstructions at Brough on Humber at the same time. 

Relatively recent archaeological excavations by the Petuaria Revisted Project unearthed evidence of another bastion in 2023, and coins from the Carausian period, which confirms that the fortifications were enhanced in the late-3rd century. But was Brough on Humber a Saxon Shore fort? To answer that question it is necessary to establish what exactly was meant by the term 'Saxon Shore'.

There is little agreement with regard the meaning of the term ‘Saxon Shore’ and the function of the forts: were they constructed at strategic points to guard against attack from Saxon pirates; or was the Saxon Shore so-named because it was settled by Saxons or the forts manned by Germanic mercenaries. Carausius is known to have used Germanic troops to operate his fleet, perhaps he settled some in his chain of Shore forts and his successor Allectus had an army of Franks defending London when Constantius attacked in 296.

However, there is little evidence of coastal raiding by Germanic pirates on the south-east coast or Picts down the east coast before the 4th century as evidenced by the five fortlets (signal stations) constructed on the North Yorkshire coast at Huntcliff, Goldsborough, Ravenscar, Scarborough and Filey during the Theodosian restructuring. Furthermore, Germanic settlers were not seen on the Humber until the early 5th century.

A more recent argument suggests these forts may have served as military ports rather then as a defensive system. It’s location on the bank of a major river estuary makes it likely Brough on Humber (Petuaria) was a naval port. But there is little evidence for anything beyond a fortified supply depot importing and exporting products to and from Britannia Inferior (Northern England and the Midlands).

The location of Brough on Humber on the East Yorkshire coast sets the Roman base too far north to be considered a true ‘Saxon Shore’ fort which were established to defend the south-eastern corner of Britain, the Wash to the Solent.  Its absence from the Notitia Dignitatum does not support the case for Brough either, yet as we have seen above, only nine forts are listed in that document when eleven sites have been identified.  

Yet we know Brough on Humber was refortified during the Carausian revolt of the Late 3rd century.  Therefore it was likely included in Carauius’s coastal defence system. Carausius would not have used the term ‘Saxon Shore’ as this term did not appear until the compilation of the Notitia Dignitatum in the Late 4th century. By this time, some of the forts along the shore may have been abandoned during the defensive reorganisations under Theodosius following the Barbarian Conspiracy of AD 367, and subsequently not included in the document. According to Wacher’s phasing the military base at Brough on Humber was finally abandoned in the last quarter of the 4th century.

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