Showing posts with label Chester. Show all posts
Showing posts with label Chester. Show all posts

10 August, 2010

Ruso and the Disappearing Dancing Girls, by Ruth Downie. Book review

Penguin, 2006. ISBN 978-0-141-02725-8. 465 pages.

Also published as Medicus and the Disappearing Dancing Girls, and the excessively portentous-sounding Medicus: A Novel of the Roman Empire. Sometimes the author’s name appears as Ruth Downie, sometimes as RS Downie.

This historical mystery is set at the Roman Army base of Deva (modern Chester) in Britain in 117 AD. All the characters are fictional.

Gaius Petreius Ruso is a surgeon in the Roman Army medical corps. Recently divorced and with an indebted family in southern Gaul to support, he takes up a posting with the Twentieth Legion Valeria Victrix in distant Britain in the hope of earning some money. He finds Britannia damp, cheerless and unwelcoming, partly because of the climate and partly because lack of funds means he is sharing a condemned house with a tribe of mice, a litter of boisterous puppies and the untidiest medic in the Army. When the body of a local barmaid turns up strangled in the river, Ruso really does not want to investigate. It isn’t his job, and he has far too many other things to do, what with chasing the mice out of the bread-bin, coping with an interfering administrator and a lovesick hospital porter, and treating an injured slave girl he bought against his better judgement and who is turning out to be disturbingly attractive. But no-one else is trying to solve the mystery, and when a second girl from the same bar also turns up dead Ruso feels he has to get to the bottom of it – especially as it seems someone is now trying to kill him too...

A Roman historical mystery investigated by an army surgeon with a complicated personal life, chaotic living arrangements, a wry sense of humour and a slowly developing realisation that he has fallen in love with a tough young woman from a different cultural background – you could be forgiven for chalking this up as a Lindsey Davis clone with a bit of M*A*S*H thrown in. Especially with a tag on the cover proclaiming “As good as Lindsey Davis or your sestercii back!”. Much as I like Lindsey Davis’ Falco novels (see review of The Silver Pigs, I find this sort of blatant association less than helpful, as it sets up an immediate preconception that risks getting in the way of the story. Is this a Roman-set mystery? Yes. Is it a Falco clone? No.

Although the novel is billed as a mystery, the whodunit plot is only one of many things going on in Ruso’s complicated personal life. He has to manage not only his duties at the military hospital, which are more onerous than usual because he and his friend and colleague Valens are covering for the absent Chief Medical Officer, but also his many other responsibilities. Ruso’s father has recently died leaving his two sons to inherit a spendthrift stepmother, a mountain of not-very-well-concealed debts and a farm in Gaul mortgaged well beyond the hilt and under constant threat of repossession. Ruso’s main preoccupation is finding the money to keep the creditors at bay while he earns enough to pay them off, by means of his salary and any other method he can think of. As a result, much of the story revolves around Ruso’s money worries, compounded by a control freak of a hospital administrator who is obsessed with charging for absolutely everything he can think of and apparently determined to channel all the hospital’s resources into expensive schemes for cutting corners and saving money. (Readers may insert the modern parallel of their choice.) On top of this, Ruso also has to find his feet in his new environment, which provides a convenient way for the reader to learn about everyday life in a Roman legionary fortress and its associated vicus*. And there is the developing relationship between Ruso and Tilla, the injured British slave he bought to rescue from an abusive master. With all this competition for Ruso’s attention – and, perforce, the reader’s – the mystery itself is rather on the slight side, though it’s resolved neatly enough in the end.

The best features of the novel, for me, were the characters and the delightfully wry humour of the writing style. Ruso, the central character, is long-suffering, rather put-upon, professional, honest, decent, serious and likeable. Much of the comedy comes from Ruso’s bemusement as he tries to make sense of his chaotic new environment and the baffling behaviour of those around him. His irresponsible, attractive, self-centred colleague Valens is the opposite, always managing to fall on his feet while deflecting any trouble onto Ruso. The amiable and lazy Regional Control Officer – “Show them we take it very seriously but whatever you do, don’t promise we’ll do anything about it” – will be familiar to anyone who’s ever had dealings with an inefficient bureaucracy. Tilla is an enigmatic character, to the reader (at least to me) as much as to Ruso. Her history and the chain of events that led to her becoming a maltreated slave in Deva is only hinted at, leaving plenty of questions that will no doubt be resolved in later books in the series. She distrusts all Romans on principle and at first is inclined to make use of Ruso as an opportunity to escape back to her home, just as she expects Ruso to make use of her by selling her to clear some of his debts. Their relationship develops slowly over the course of the novel, and still has scope for further development by the end.

Delightful historical mystery set in second-century Roman Britain, told with wit and wry humour.

*A vicus is a civilian settlement outside a military base, a sort of cross between a suburb and a shanty town.

09 June, 2009

Chester in the seventh century: surviving infrastructure

Modern Chester was founded in around 74 AD as the Roman legionary fortress of Deva, later acquiring part of the name of the Twentieth Legion to become Deva Victrix. It clearly had a large number of impressive Roman buildings, perhaps more impressive than most Roman cities in Britain. Deva was 20% bigger than the other legionary fortresses in Roman Britain (e.g. Eboracum, modern York), and contained the enigmatic Elliptical Building, so far unique in the Empire. The purpose of the Elliptical Building remains unknown, but it must have been an impressive structure in its day. Chester also had the usual components of a legionary fortress, including a headquarters building (principia), smart houses for the commander (praetorium) and senior officers, amphitheatre, stone defensive walls and a main baths building (thermae), not to mention a large harbour and a bridge crossing the River Dee. How much of this was still standing in the seventh century, and can we tell if people were still using it for anything?

Evidence

Documentary

Ranulph Higden, a monk at the abbey of St Werburgh in Chester (later the cathedral) wrote a description of Chester in the mid fourteenth century. He described underground passages (the sewers), huge stones inscribed with the names of ancient men (tombstones, or perhaps also other monuments or inscriptions?), and vaulted dining rooms (perhaps parts of the main bath building [thermae]) (quoted in Mason 2001). Evidently substantial parts of the Roman infrastructure were still standing at this date, getting on for a thousand years after Roman government came to an end in Britain. Say what you like about the Romans, they built to last.

Archaeology

Headquarters building
In the headquarters building, the rooms along the rear of the cross-hall were refloored several times during the fourth century, and the room west of the shrine-room (aedes) was converted into a secondary shrine. Mason (2001) gives no date for these repairs, but since there were several they presumably span quite a long period of time and indicate regular use and maintenance in most of the fourth century, if not later.

Elliptical Building
In the baths suite attached to the Elliptical Building, a new doorway was inserted and the mortar bedding for its timber door sill produced a find of 24 coins dated the reign of Emperors Valens and Valentinian (364-75 AD). The hypocaust was rebuilt, and part of the suspended floor was found still intact when excavated in 1969. Gold-working crucibles were found at the north end of the building, together with a gold solidus of the Emperor Magnentius (350-353 AD).

Coins of Theodosius I (379-395) and Arcadius (395-408) have been found in Chester, but no coins of Honorius (became Emperor in 408).

Excavation in the centre of the fortress has shown that there was no extensive complex of post-Roman timber buildings as at Wroxeter in this area. Possibly such structures existed elsewhere in the fortress and have not been discovered (or not recognised), but there is no evidence for them. David Mason states that the various timber buildings identified in Chester on various digs so far are now thought to belong to the Anglo-Scandinavian town of the ninth and tenth centuries.

Bridge
Not much is known about the Roman bridge, except that it was on more or less the same site as the current Old Dee Bridge, which was built in the medieval period. It is not known how long the Roman bridge stood. The location of its replacement on the same site may indicate that the Roman bridge remained standing and in use long enough for the street plan of Anglo-Scandinavian and medieval Chester to become fixed and so dictate the position of the crossing. Or it may reflect the constraints of geology/geography, for example if it happens to be the only sensible place in the vicinity to build a bridge.

Baths complex
The thermae courtyard was repaired and resurfaced throughout the fourth century.

When the thermae complex was destroyed by development in 1964, parts of the walls were still standing in situ to a height of up to 13 feet (4 m), hypocausts and mosaic floors were still intact, and large sections of collapsed roofing vaults (barrel-vaulted concrete, estimated to have stood 53 feet above floor level) lay on the floors. A layer of “dark earth” containing charcoal and bits of animal bone had accumulated to a depth of 1 foot (30 cm) over the tepidarium floor, implying a considerable period of residential occupation. It is not known when the roof vault collapsed. However, if the “vaulted dining rooms” mentioned by Ranulph Higden refer to the vaulted and decorated bath complex, then parts of the building were still standing and still roofed in the middle of the fourteenth century.

Harbour
The harbour and the rest of the Dee estuary downstream of Chester has been slowly silting up since the end of the Ice Age, and the harbour is now the low-lying dry land of Roodee racecourse. In the Roman perod it was a busy harbour and may have been the base for part of the Roman naval fleet. Shipping is recorded as having trouble getting upstream to Chester in the late medieval period, according to Mason. He also says that the Anglo-Scandinavian town of the ninth and tenth centuries relied on trade, and that the street frontages were cleared of Roman rubble because they were the most valued as commercial premises. If this is correct, it implies that the harbour was still capable of taking trading shipping at a useful volume, at least for shallow-draughted ships like those used by the Norsemen, until at least the tenth century. The harbour would presumably therefore also have been similarly functional in the intervening period.

Place name

It’s worth noting that there is no trace of the Roman name Deva Victrix in the modern name of Chester or in the names Bede knew for the city in when he wrote his Ecclesiastical History in 731:

…which the English call Legacaster and the British more correctly call Caerlegion…
--Bede, Ecclesiastical History of the English People, Book II Ch. 2

Bede was writing in Latin and called the city Urbs Legionis. This translates as “City of the Legion”, as do the English and British names he quotes, so the three names are really the same name in three languages.

This contrasts with some other Roman fortresses and cities, such as Winchester, Lincoln, York, Londinium, Wroxeter and Carlisle, where elements of the Roman name can be traced in the modern name. In turn, this may indicate that whatever Chester was used for after the Romans left, and whoever was using it, the Roman name was either discarded or lost.


Interpretation

The coin evidence may suggest that regular Roman Army troops were still stationed in Chester, getting paid in Imperial coinage and repairing and maintaining the fortress buildings up to about the end of the fourth century, but not during the reign of Honorius in the early fifth. It is of course possible that coins of Honorius circulated in Chester and that none has yet happened to be discovered by archaeology. However, given that the usurper Emperor Constantine III invaded Continental Europe from Britain in 407, presumably with an army, it is quite plausible that he took Chester’s garrison with him.

Chester hosted a major synod in 601 (Annales Cambriae), which is probably the same event as the meeting recorded by Bede in 603 or 604 and attended by seven bishops and “many very learned men” (Bede Book II Ch. 2). The synod and the possible ecclesiastical importance of Chester was discussed in an earlier post. It also has implications for the state of the surviving infrastructure. Seven bishops probably each brought a sizeable retinue, as no doubt did Augustine of Canterbury. If Chester was the site, this implies it was:
(a) an important and prestigious place, suitable for hosting a gathering of VIPs;
(b) had enough infrastructure to cope with them and their retinues in suitable style;
(c) was sufficiently well-connected to transport networks that a large number of people could be expected to travel to it;
(d) perhaps that it had some connection with the Brittonic Christian church or an important official thereof (perhaps a Bishop of Chester, as discussed earlier.

Chester in the seventh century probably still had the following infrastructure:

  • A fortress wall (possibly not fully intact – see earlier post);

  • A functioning harbour, at least for shallow-draughted vessels;

  • A bridge crossing the River Dee;

  • Part or all of the main baths complex (thermae), still standing and still roofed;

  • Probably some or all of the similarly robust structures, such as the headquarters building and perhaps the Elliptical Buildng, were also still standing and roofed, since they had been kept in good repair up to at least 400 AD and would have taken some time before they fell down;

  • Roman streets and roads on the alignments still in use today (and maybe some others that have since been lost);

  • A population living in and/or around the fortress, probably at a low density


The location of the synod suggests that the Chester may have been a centre of ecclesiastical power, as has been suggested for Wroxeter. It may also have been a centre of secular power, or the secular power (i.e. the king or local sub-king) may have been based elsewhere, again as has been suggested for Wroxeter.

Chester’s Roman name seems to have gone out of use some time before 731, since Bede knew the city as “City of the Legion” in three languages and not as Deva, Deva Victrix, or any derivation thereof . This isn’t universal for ex-Roman cities in Britain, since Bede knew his local city (modern York) by its Roman name of Eboracum. Nor does it just reflect the limits of Bede’s knowledge, since whoever wrote Annales Cambriae also knew Chester as “City of the Legion”, not as Deva.

The absence of Chester’s Roman name by 731 may suggest either a temporary period of abandonment during which the name was forgotten, or a deliberate decision not to use the Roman name. I would lean towards the deliberate decision, since it seems unlikely that Latin-speaking literate Brittonic churchmen would not have been perfectly capable of reading the city name off milestones or inscriptions if they wanted to, even if all other records had somehow been lost. Perhaps the local population had always called the fortress “the city of the legion”, reflecting its military function, in the same sort of way as the Gaelic name for modern Fort William is An Gearasdan, “the garrison”.


References
Mason DJP. Roman Chester: city of the eagles. Tempus, 2001, ISBN 978- 0-7524-1922-0.
Bede. Ecclesiastical History of the English People. Translated by Leo Sherley-Price, Penguin Classics, 1968, ISBN 0-14-044565-X

Google Maps links
Chester
Fort William

26 May, 2009

A Bishop of Chester?

In an earlier post, I discussed the likely survival of Chester’s Roman defences into the early medieval period. Clearly some of the Roman fortress wall was still standing at the time, since parts of it are still standing now, but it may not have been fully intact.

During Roman government, Chester was a legionary fortress situated in the territory of the Cornovii, whose tribal capital was at Wroxeter (Viroconium Cornoviorum). Could it have become an important ecclesiastical centre in the early medieval period?

Evidence

Annales Cambriae

601 - The synod of Urbs Legionis [Chester].
Annales Cambriae

Some of the dates in Annales Cambriae are two or three years different from those of the same events given by Bede (e.g. the date of the battles in which Edwin of Northumbria and Catwallaun of Gwynedd died), so this is very likely the synod referred to by Bede at which Archbishop Augustine of Canterbury met a group of Brittonic bishops at a date in 603 or 604 (Ecclesiastical History, Book II Ch. 2). Bede doesn’t specify the location of the meeting, but says that it was attended by seven bishops and many very learned men mainly from Bangor-Is-Y-Coed. Bangor-Is-Y-Coed is about 18 miles from Chester, so this would be consistent with the synod being held in Chester.

Archaeology

A lead salt-pan discovered at Shavington, near Nantwich, bore the inscription Viventi [Epis]copi (White & Barker 2002; Keith Matthews website). The first word translates as “of Viventius”, and the second could mean either that Viventius was the episcopus or that Viventius was subordinate to the episcopus.

Episcopus was used of a bishop (whence the modern term “episcopal”). However, it could also mean “overseer” or “supervisor”. So the inscription could refer to a bishop who owned a salt works, or to the foreman of a salt factory. It is impossible to rule out either, although as Viventius is the name of a Christian saint, I’m inclined to agree with Keith Matthews that a bishop is a more likely interpretation than a factory overseer.

Interpretation

The Synod at Chester must have been an important event, at least in the opinion of whoever thought it worth recording in Annales Cambriae. So it is a reasonable interpretation that Chester in 601/603 was a centre considered suitable for such an event. This may reflect surviving infrastructure capable of accommodating a large number of VIPs – seven bishops and their retinues, plus “many learned men”, probably amounted to quite a lot of people. It may also indicate that Chester was a prestigious site, the sort of place where one would choose to invite a foreign dignitary (Augustine). If it was also under the control of a wealthy churchman, that would fit very well.

Salt was a vital commodity, needed for preserving food over the winter, and so salt production can be expected to have continued in some form long after the end of Roman administration. If the bishopric of Chester controlled the income from a salt works, that could have provided a substantial source of revenue in addition to whatever income was gained from the local agricultural population. An additional source of revenue would have helped to maintain Chester as a prestigious site (since it had the resources to maintain, repair or replace buildings), and contributed to the bishop’s ability to put on a big event like the Synod.

Cities run by bishops existed in fifth-century Gaul, where Sidonius Apollinaris, bishop of what is now Clermont-Ferrand in the Auvergne, governed his city and negotiated with the local king (of the Goths) in 470-480. The other city known from the civitas of the Cornovii, Wroxeter, had a complex of impressive timber houses in Roman style built on the site of the baths basilica in the late sixth century, and it has been suggested that the frigidarium of the baths was used as a church (as happened in Leicester) and that the rebuilding was organised by a bishop who controlled the city (White & Barker 2002). Perhaps Chester was also run by a bishop in the early 600s – and perhaps his name was Viventius…


References
Annales Cambriae, available online.
Bede. Ecclesiastical History of the English People. Translated by Leo Sherley-Price, Penguin Classics, 1968, ISBN 0-14-044565-X
Mason DJP. Roman Chester: city of the eagles. Tempus, 2001, ISBN 978- 0-7524-1922-0.
White R, Barker P. Wroxeter: Life and death of a Roman city. Tempus, 2002, ISBN 978-0-7524-1409-7.

Google Maps Links
Chester
Wroxeter
Shavington
Bangor-Is-Y-Coed

10 March, 2009

Chester in the seventh century: the fortress defences

Roman Chester was founded in around 74 AD as the legionary fortress of Deva, later called Deva Victrix from the name of its garrison, the Twentieth Legion Valeria Victrix. As a legionary fortress, it would obviously have been provided with a defensive wall. What were the defences like, and were they still standing in the seventh century?

Evidence

The Roman defences

The initial Roman fort built in 74 AD or thereabouts had a turf and timber rampart. This may have been intended as a temporary structure from the start, and was soon replaced by a stone curtain wall. The date of completion of the stone defences is unknown, but usually placed somewhere around the turn of the first and second centuries (Mason 2001). On the south and west sides of the fortress, the Roman defences were demolished in the medieval period and replaced by defences extending to the river, so only the foundations and first few courses of the Roman walls survive to be recognised in archaeological excavations. On the east and north sides, some stretches of the Roman wall still stand to a considerable height with the later medieval walls on top.

Chester’s curtain wall was unusual, as it was entirely built using the monumental construction technique called opus quadratum, usually reserved for prestige structures such as gates. Large stone blocks up to 6 feet (1.8 m) long and 3.5 feet (1 m) wide were laid in courses 10–15 inches (25–36 cm) high, without using mortar. The wall was 4.5 feet (1.35 m) thick, reducing to 3.5 feet (1 m) at the top, and had an elaborate moulded cornice below the parapet (Mason 2001). This flashy form of construction is consistent with Chester having a higher status than other legionary fortresses in Britain (more on this in a later post).

The wall was built immediately in front of the original rampart, and the space between the wall and the front face of the old rampart was filled with rubble mixed with clay (mixed with mortar in the section between the south and east gates. This may indicate different work parties using different techniques in different sectors, or different phases of construction (Mason 2001).

How long did the defences stand?

A section of the north wall was taken down and rebuilt in the late nineteenth century, when it was found to contain re-used Roman tombstones and pieces of architectural sculpture. This could hardly belong to the original stone wall, as the fortress had only been in existence some 20 years at the time, surely not long enough to have generated large quantities of tombstones to be requisitioned for building work. Some of the tombstones commemorated serving legionaries who were married and thus probably third century. One commemorated Gabinius Felix, a soldier of legion II Augusta, and gave his legion the title Antoniniana, which was current in 213–222. The tombstone was very weathered, suggesting it was re-used in the wall no earlier than the late third century.

Further investigations have suggested two distinct phases of rebuilding of Chester’s curtain wall, both using large quantities of recycled Roman masonry and tombstones. In one phase the replacement wall was about 10 feet thick, roughly twice the thickness of the original wall, and this has been identified on the north wall immediately west of the north-east corner, and on the west wall north of the west gate.

In the other phase, the replacement wall was about 5 feet thick, roughly the same as the original wall. This rebuild has been identified on the north, east and west walls of the fortress. A section of this rebuild south of the east gate (at the Old Public Library on St John’s Street) allowed some of the sequence to be reconstructed. This showed that the ditch in front of the original Roman fortress wall had silted up completely to ground level, and on top of the soft fill lay a mass of heavy rubble including some damaged facing stones from the fortress wall. This is consistent with the wall having collapsed forwards and outwards (the wall leans outwards in the sections that are still standing further north along the east wall). This collapse might have been spontaneous or might have been deliberate demolition to make the site safe before beginning the rebuild. The rubble had been covered with a layer of sandstone brash up to 1 foot thick, and the wall rebuilt from the fourth course upwards, to the original width of about 5 feet, backed by clay instead of the original mortar, and containing at least one moulded block re-used from somewhere else. This rebuilt wall had itself collapsed, forwards and outwards again, onto the layer of sandstone brash. The rubble from this second collapse had eventually combined with the collapsed and weathered rampart behind to form a low mound. David Mason says there was evidence for a subsequent refortification, before the existing medieval wall and massive ditch was built in its current alignment probably in the late twelfth century. (Unfortunately, he doesn’t specify what the evidence for the post-Roman pre-medieval refortification consisted of).

Neither of the rebuildings can be securely dated. Mason concludes that the narrower rebuild probably belongs to the first quarter, of the fourth century and may be associated with an overhaul of Britain’s infrastructure and defences after Constantine the Great came to power. The thicker rebuild is identified as later on the basis of constructional technique. A single coin of Constantius II Caesar (324–337) was found in the thicker rebuild east of the north gate. Mason says that it means little by itself but does not elaborate; my guess is that a single coin could have been picked up accidentally along with the recycled building material and could have come from anywhere. At one point (p.211) he says the thicker rebuild could belong to the overhaul of army installations conducted by the elder Theodosius in about 370 AD, after the Barbarian Conspiracy, and at another (p. 204) he says it could be post-Roman and perhaps as late as the tenth century.

Documentary evidence

Annales Cambriae

601 The synod of Urbs Legionis [Chester].
--Annales Cambriae

This is probably the same synod mentioned by Bede for 603 or 604 AD. The use of Chester as a site for a major synod indicates that the city was still important, but does not necessarily say anything about the state of the defences.

The Anglo-Saxon Chronicle mentions Chester twice at the end of the ninth century:

AD 894.
....they [the Danish army] marched on the stretch by day and night,
till they arrived at a western city in Wirheal that is called
Chester. There the army could not overtake them ere they arrived
within the work: they beset the work though, without, some two
days, took all the cattle that was thereabout, slew the men whom
they could overtake without the work, and all the corn they
either burned or consumed with their horses every evening.


AD 907
.... Chester was rebuilt.
--Anglo-Saxon Chronicle

The 894 entry suggests to me that the English army tried to overtake the Danes before they arrived “within the work” at Chester, and therefore that Chester still had defences that were sufficiently serviceable to be of military use. The Chronicle often refers to “a work” in a context that implies it meant defensive earthworks. It also suggests to me that Chester and/or its immediate surroundings had sufficient of a population to have cattle and corn. The 907 entry suggests to me that Chester’s defences were incomplete enough to require rebuilding.

Interpretation

Clearly, the parts of Chester’s Roman walls that are still standing now (north wall and the east wall north of the east gate) would have been standing in the seventh century. It is impossible to be sure how much of the west and south walls were intact before they were demolished to extend the defences.

The second collapse of the rebuilt east wall south of the east gate was apparently left as rubble long enough to combine with the remains of the collapsed rampart behind, implying a long period without repair. If David Mason is correct that there was a subsequent refortification which predated the medieval wall, this is consistent with a long period of disrepair during the early medieval period, followed by a refortification either when the Danes briefly took the city in 894 or when “Chester was rebuilt” in 907. Since the wall was rebuilt to its original width and on its original foundation, it’s a reasonable first approximation that the rebuild may have stood about as long as the original. If the original stone wall was finished in the early second century (say 110 AD), and was demolished immediately before the rebuild was carried out in the early fourth century (say 310 AD), the original wall stood for about 200 years. If the rebuilt wall managed the same, it would have collapsed in the early sixth century (say 510 AD). It’s unlikely to have collapsed while the Roman Army was still in residence (i.e. up to c. 400 AD) or one would expect it to have been repaired again, and is perhaps unlikely to have stood much beyond, say, the early seventh century given the implied long period of disrepair. So we could tentatively assign a date of c. 500 AD, plus or minus a century or so either way, for the collapse of the rebuilt wall south of the east gate.

It is possible that the thicker rebuild of the curtain wall using recycled stone was part of the 907 rebuilding. However, the “refortification” of the east wall south of the east gate mentioned by David Mason presumably did not conform to the same pattern as the thicker rebuild, or one would expect him to have said so. So either there was a reason why the same fortification used different techniques, or they occurred at different times. I favour the latter as a simpler explanation.

On balance, I would suggest the following approximate sequence:

  • AD 100 approx – stone curtain wall built.

  • AD 260 – 310 approx - Chester largely abandoned while the Twentieth Legion is fighting elsewhere in the Empire. The ditch silts up and parts of the curtain wall collapse due to lack of maintenance.

  • AD 310 approx – Damaged parts of Chester’s curtain wall repaired to original width.

  • AD 370 or later – Other damaged parts of Chester’s curtain wall, which had presumably not needed repair in 310, rebuilt to double width.

  • AD 500 approx (plus/minus a century) – Part of the wall rebuilt in c. 310 collapses south of the east gate and the breach is ignored, the rubble being left to combine with the collapsed rampart. Either the breach was still defensible with a sufficiently large and determined force, or Chester was not an important defensive structure at the time, or any repair/refortification has not left any evidence).

  • AD 907 – Chester refortified by Aethelflaed Lady of the Mercians to create a defensive burh.


References
Full-text sources available online are linked in the text.
Mason DJP. Roman Chester: city of the eagles. Tempus, 2001, ISBN 978- 0-7524-1922-0.