The Roman Bath at Isthmia and the Hexamilion, Part I

There’s an old joke:

You know how you date a fortification wall, right? 

To be honest, it’s pretty hard; they can be so defensive!

All kidding aside, Guy Sanders very recently published an article further unpacking his efforts to revise the chronology for certain common and important types of Late Roman pottery (and lamps): “Bridging the Grande Breche Rethinking Coins, Ceramics, Corinth, and Commerce in the Centuries Following AD 500” in Archie Dunn’s edited volume, Byzantine Greece: Microcosm of Empire? Papers from the Forty-sixth Spring Symposium of Byzantine Studies (2024). This is not only important work for our understanding of Late Roman pottery across the Mediterranean (especially in the Eastern Mediterranean), but, more significantly, for our effort to understand the history of monuments, cities, and communities during the centuries traditionally associated with “the end of antiquity.”

In this publication, he makes a brief reference to the date of the Hexamilion wall, the famous six-mile wall built across the Isthmus of Corinth. Tim Gregory argued that this wall was likely built in the early 5th century, early in the reign of Theodosius II, and in response, perhaps, the Visigothic invasion at the end of the 4th century. Sanders proposed a Justinianic date for the Hexamilion.

A Justinianic date is not implausible partly because there is a good bit of literary and some epigraphic evidence to suggest that Justinian was involved in re-fortification of Corinth and the Peloponnesus. Gregory outlines it in his volume in the Isthmia series. He notes that there is textual evidence for two waves of fortification in the region in Late Antiquity, one of which Procopius attributes to Justinian who rebuilt an earlier structure. This contributed in part to Gregory’s decision to attribute the construction of the Hexamilon Wall to Theodosius II and the later construction of the fortress at Isthmia to Justinian. That said, it is not impossible that the political agenda present in Procopius — particularly in light of the rhetorical complexity and snarky ambivalence in his works — might deliberately confuse or complicate the attribution (and chronology) of fortifications on the Isthmus. 

In other words, there is room for Sanders to be correct in his suggestion that we re-date the Hexamilion to Justinian’s reign especially in light of what we know about Justinian’s investment in the Isthmus and the generally later drift of our ceramic chronologies. 

With this context, we should attend to Sander’s collegial provocation. It is rather brief: 

One context at Isthmia crucial for the dating of the wall contains an African Red Slip from 73A bowl dated by Hayes to ca. 420-475 and indicated that the new lamp chronology is closer to reality. The bowl is of a type found in ’the deposits of c. 460-75’ discussed above. My later chronology for this material would therefore place the construction of the wall in the mid-6th century.

~

This argument is intriguing to me because I spent about a month this summer working with Scott Moore and Richard Rothaus on the stratigraphy of the Roman bath at Isthmia and the material from it’s post-abandonment phases. The pot that Sanders refers to is IPR 76-6 in the Isthmia system. 

It just so happens that this particular pot comes from the Roman bath at Isthmia. The north wall of the bath forms part of the Hexamilion wall. Thus, the sequence of abandonment and reuse of this building has become an important source for understanding both the end of the Panhellenic sanctuary at Isthmia and the construction of the Hexamilion (as well as the history of the area around the fortress in the 7th and 8th centuries). The pot is noted in an 1981 Hesperia article by Birgitta Wohl titled “A Deposit of Lamps from the Roman Bath at Isthmia.”

IPR 76-6 specifically come from 76-MCO-006. Wohl connects this pot with a level associated with a significant “deposit” of Roman lamps from Room I, II, and VI of the Roman bath. For those of you who know the Bath, Room VI features the massive monochrome mosaic for which this building is well-known. This particular deposit was from above the floor of Room I and VI and the deposit of lamps from this level with some references to the other material present has now appeared in her recent volume in the Isthmia series.

The level is interesting because it has a clear place in a depositional sequence associated with post-abandonment activity in the bath (although, to be honest, I have no idea why this level produced so many Roman lamps!). Wohl argues that the bath appears to have been abandoned for some period of time based on a thin layer of hard-packed earth on top of the mosaic floors. This Wohl identifies as a layer of wash that entered Room I of the bath after it went out of use. This wash entered Room I, at least, through the door in north wall (before it had been closed by the Hexamilion) and also presumably broken windows of the bath as window glass was found in these abandonment levels. Some of this hard-packed earth level appears to continue into Room VI, to the south of Room I.

At some point after the deposit of this layer of wash, the roof was removed from Room I. The removal of the roof from this rooms most likely occurred immediately prior to or even during the construction of the Hexamilion wall against the northern wall of the bath. At this time, the bath would have served as a useful level area for work and the removed roof perhaps as a useful source of bricks and other rubble for construction. As part of the construction of the Hexamilion, the north wall of the bath was thickened by a field stone and mortal wall. This wall stood atop the mosaic floor in Room I, but also cut through the hard-packed level on top of that floor. 

Wohl then supposes that during a time of abandonment after the construction of the Hexamilion wall debris was dumped into Room I (and perhaps Room II?) and spilled down into Room VI on top of the hard pack abandonment layer. This debris constituted a burned black level and was evidently trash and soil from elsewhere at the site dumped haphazardly into Room I and spilling out into Room VI further south. If Room 1 didn’t have a roof, then this might make it a convenient place to dump trash.

It must be that this material became commingled with the material from immediately above the mosaic floors during excavation. Or at least this is what Wohl must have believed because she connected IPR 76-6 with the lamp deposit despite it coming from a context only centimeter or so above the floor level. The excavator, however, did note that the soil in this level was soft sandy soil which became blacker closer to the floor level, but stressed a number of times that the bowl was immediately above the mosaic floor and NOT from the burned black level.

More problematic still for Wohl is that the pot does not appear to come from Room I where the lamp deposit was found, but Room II which appears to have had a slightly different history from Room I. Like Room I, it probably had at least part of its roof dismantled. It also had a door to the exterior of the building in its north wall. That said, it is hard then to determine whether the bowl was found on a harder layer of wash that perhaps entered Room II through the same process as the wash entered Room I, if such a layer existed in Room II; or from a similar burned black level present in Room I which also contained the lamps; or from an entirely different episode of burning that seems to be associated with the level immediately above the mosaic floor in the south east corner of Room II. For whatever it is worth the level with the bowl (76-MCO-006) appears to include no lamp fragments (as near as I can tell; annoyingly Wohl does not identify the contexts for the lamp fragments that she publishes in her 1981 article and her 2017 Isthmia volume). 

Thus, the pot in question here has problems: IPR 76-6 is not from Room I or Room VI, but from Room II. It is also from a strata that may or may not be the same as the strata associated with the lamp deposit. It is neither clearly associated with the hard packed layer immediate above the floor or from the burned soil that is similar to the burned context where the lamp fragments were found. This is important because if it is from the layer of hard-packed earth closest to the floor, then it dates to the time after the abandonment of the bath but before the construction of the Hexamilion and would be useful for dating the Hexamilion wall. If, on the other hand, it is from the material dumped into Room I (and perhaps Room II), then it dates to after the construction of the Hexamilion. 

To be clear, there is no real way that Sanders could have known any of this. So his argument isn’t wrong in the basis of what he could have known about the bath from published reports. In fact, it took me a weekend full of sleuthing to sort this out (and, I should stress here, I’m still not sure that I have it all right!).

There are, of course, more complications still, but these are, as the kids say, useful complications and since I’m rambled on enough for today, I’ll return to those tomorrow.