Wednesday, 9 December 2009

Reconstruction techniques at Pompeii

One aspect that every Pompeian scholar is bound to come up against during the course of their research is the question of what is and isn't reconstructed at Pompeii. In the course of my own work I've examined walls and doorways time and again with this in mind. Now I'd like to open it up to other researchers to kindly point out some details that can be put together as recognised patterns of reconstruction that are otherwise unrecorded in the excavation reports, etc. Please post a reply if you can help with this!

Mortar - what is ancient and what is modern?
This is a big question because so much relies up on viewing a mortar up close. Occasionally it's possible to know what is a modern repair like repointing (to keep the opus incertum stones from falling apart and allowing the wall to collapse, etc), but does anyone have other markers to point out?

Blocked doorways: Blocked in antiquity or in modern times (and why)?
20th century site workers (muratore) developed a method of filling in doorways but leaving gaps at each side of the doorway to show that it was a modern fill. Of course, the largest clue lies in the modern mortar, but does anyone have further thoughts on this and/or why the muratore thought this was necessary?

Earthquake damage to walls in AD 63: How to know?
John Dobbins and the Pompeii Forum Project have carried out some great work on noting wall failure patterns and the subsequent repairs. But does anyone else have some tips?


Eppu Viitanen said...

This is a very good topic - I hope that others reply as well!

Having worked on the buildings archaeology at the insula IX 3 with the Finnish project, reconstructions are often on my mind in the field and even afterwards when we're processing the data. The areas we've so far worked with were excavated in the 1840's which means over 150 years of restoration and reconstruction.

Some bits are easier than others. E.g., anything towards the top of the wall is naturally suspect. Some of the earlier reconstructions were made using large blocks in manners that the ancients never used (as far as I know). I'm pretty sure there is an Italian article documenting the ways the restorations were made in the Bourbon era - my apologies for being unable to dig it up right now. They are pretty clear and easy to discern at least in our insula.

Checking the mortars at the top of the walls is usually difficult and with the way the walls have been repeatedly pointed after the original dig, comparing the mortars might not be the most efficient way.

After working at the site for a while I think it is possible to make the differences of how the stones have been laid, what stone types have been used etc. compared to the bits that are certainly ancient. The ancient bits tend to be more regular and much neater compared to most reconstructions. But sometimes it is very difficult even when you know that the wall in front of you must be new: one of the large central images in the main triclinium of the House of Marcus Lucretius (IX 3,5/24) was removed by demolishing the wall behind it ca 1850 and it is pretty much impossible to see where the gap was on the other side of the wall even though you know it must be there!

We have also used old photographs and the model in the Naples museum to recognize the new bits. In addition, the report by Edward Falkener has given us clues to the work done immediately after the excavation. E.g., one partition wall was demolished and at least one door was blocked.

So, basically I started by looking at the most suspicious locations and trying to understand the differences between the certainly old and the certainly new. Using all possible old (and new) documentation helps as well. I guess there is no easy way and now that we're about to move out of the 1840's excavation area to the 1870's area, it'll be interesting to see if the reconstructions change!

James Andrews said...

As Eppu has just mentioned this is an interesting subject but one that maybe is really difficult to generalise about - what I mean is I think we have to go on a wall by wall basis such are the variables.

The problem doesn't just concern the restorations of the 18th or 19th centuries either. The re-pointing work of Maiuri, particularly in the excavations of the 1920s, was very heavy handed indeed. In the Casa dell'Efebo this even covered over beam sockets which are only visible in a couple of excavation photographs.

It doesn't help either when ancient masonry has been re-used in the restoration work. There are some instances of this at Herculaneum that are very difficult to differentiate from their ancient counterparts, but I guess the same can also be said for many walls at Pompeii.

Earthquake damage I think is a very tricky subject indeed and one cannot simply go on examples of walls that have just been executed in a slip-shod fashion - they could belong to almost any building phase. Perhaps more certain are clear patches to walls that have cracked. As Jo points out, those in the Forum are quite clear. But of course, why should these belong to the 62 earthquake and not later ones?

All pretty tricky.

Eugene Dwyer said...

Many contemporary descriptions (like that of Falkener) of the work at Pompeii exist in visitors' accounts. I recently gave that of W. D. Howells (1867) a second look: "They dig down about eight or ten feet, uncovering the walls and pillars of the houses, and the mason, who is at hand, places little iron rivets in the stucco to prevent its fall where it is weak, while an artist attends to wash and clean the frescoes as fast as they are exposed. ..." (Italian Journeys [Marlboro VT 1988] 58) It is very useful when the visitor knows something about building!

The article on Bourbon restoration is: Mario Pagano, "Metologia dei restauri borbonici a Pompei ed Ercolano," Rivista di studi pompeiani V (1991-1992) 169-191.

Eppu Viitanen said...

James's comment is to the point - it is very difficult to generalize. Attacking the walls with as many sources of information as you can possibly have is necessary...

Thank you for both references, Mr Dwyer! I wonder if the rivets used in the 19th century were the ones that have usually been removed (the ones usually set in a sort of a star-shape) leaving mysterious little holes in the plaster?

Jo Berry said...

Posted on behalf of Wolfgang Ehrhardt:

'The subject s not new at all. In the series of "Häuser in Pompeji" lines like _._._ inside the grey tone graphics of each wall indicate the end of the ancient and the start of the reconstruction. The case in Herculaneum seems to be more difficult as Th. Ganschow, Untersuchungen zur Baugeschichte in Herculaneum (Bonn 1989) demonstrated. The differentiation by analyzing the used mortar is in some cases not helpful because the restorers mixed the ancient sand and small particles of the ancient mortar, plaster etc. with their mortar. And in all cases you have to look on both sides of a wall because the outside face may be clear of any plaster. Thus our restorer R. Meyer Graft who worked with the project „Häuser in Pompeji“ proposed to mixed with the modern mortar a granulated of modern brown glass. But of course there will be other definitely modern materials. To separate ancient and modern parts of the ancient buildings it is helpful to look of the pattern how the stones are arranged and to countercheck the observations with old photographs, designs and the Pompeii model in the Museo Nazionale Napoli. Thus I agree with the comments of Lupu, Andrews and Dwyer. It is easier to analyze the plaster under the wall paintings.

Eric Poehler said...


The most obvious way to identify reconstructed walls are the seams in the fabric of the masonry, sometimes with bricks used to mark the boundary between ancient and modern. An example can be seen in the images of the Casa di Successus (I 9, 3). Even without the boundary so clearly marked, it is the interface between different fabrics of masonry and their mortars that reveals the location of different phases of construction.

Unfortuneatly, there are few other truly telling signs and it is instead only through careful looking or even excavation that can tell that a wall is a modern reconstruction. To illustrate this, let me expand upon the idea with “A Tale of Two Walls”. The southern and northern boundary walls of the area under investigation by the Pompeii Archaeological Research Project: Porta Stabia - directed by Steven Ellis and Gary Devore – have been found to have be either reconstructions of an ancient wall or a completely ex novo construction. It was only after considerable scrutiny and argument, however, that such determinations could be made. How these determinations were made might be of value for others facing such questions.

First, the southern wall. During the excavation of the toilet in the service quarter of the southernmost property, the chronology of the wall currently standing came into question when two lower, now destroyed walls on a slightly different alignment came to light (see Ellis and Devore 2009). The unusual construction of the wall in large irregular stones, several of which were scored with what appeared to be masons marks, was noted. A heavy smear of modern mortar used to consolidate the exterior face of the wall prevented systematic investigation of the ancient mortar. This consolidation was not found on the upper levels of the wall, the construction style of which was still different again, indicating to us that the top was modern. Differences in construction styles on either side of this segment of the masonry did suggest, however, this part had a different history. Why this middle part of a long wall should be different was not clarified until we discovered lapilli beneath the wall and even embedded in the once-wet mortar below the first course of stones. Only this observation allowed us to finally realize that this section wall had collapsed after the area was excavated due to the pressure of materials behind it. This interpretation is supported by the existence of two modern buttresses farther to the west along the same wall, which may have been added in response to this collapse. Whatever the case, we now know that the wall we see has a complex modern history – rebuild of an ancient wall, consolidation of its face with modern mortar, and another rebuilding over the top of that.

Eric Poehler said...


In the north, the boundary wall separating the private space of the insula from the public space of the alley behind the Odeon also came into question. We had previously noted the change in the shape of space when a wall that appeared in the 2006 excavations seemed to continue to the north beyond the current boundary wall and into the public space of the alley. Excavation on the opposite side of this wall in 2008 (see Ellis and Devore 2009), revealed no trace of this wall. Instead, the foundation for the northern boundary wall terminated at the junction with this other wall. We now believed that the western portion of our northernmost property was once part of an open public space between the Odeon and the Quadriporticus. Analysis of the visible masonry showed a clear mortar change as part of a new build over the top of the earlier northern boundary wall, which then extended to the west, giving the area its final shape. As we began the excavations in the area to the south of this latest wall in 2009, two facts raised new suspicions about this late, western part of the wall. First, we noticed larger stones that we scored with rough lines in crossing patterns in this section of the wall that were similar to those found in the southern boundary wall, now known to be modern. More important, however, was the complete lack of a foundation for the final part of the wall. Indeed, the bottom of the wall is merely mortar poured to fill a trench. Again, lapilli in the foundation pour suggested this entire section of the wall was modern. This hypothesis was confirmed when we looked at the elevation of the foundation: in order to dig out such a foundation, the ground level in the area must have significantly higher than the threshold stones for the Odeon’s south wall.

The methodological morals to these archaeological stories, I believe, are three fold. First, in making the determination of what is ancient and what is modern, it is not safe to assume that because one section of modern masonry has been identified that it is the only one. Second, there is a need to apply the same mental flexibility used in thinking about the shape of space created by ancient architecture to potentially modern constructions. Don’t assume that modern masonry will always follow the ancient. Third, the lowest part of the wall is the oldest it is the bottom that will most likely be the ancient part; work from the known to the unknown, in this case ‘up’.

Finally, a note on identifying earthquake damage. We found that there was a systematic collapse and rebuilding of all of the northern properties that appears to have occurred at the same time. The evidence, which if found in only few examples or found in early stratigraphic sequences should not be connected to the earthquake, is in the form of a horizontal change in the vertical relationship between walls. That is, a great many walls abut another wall at a lower level, bond with the later wall at a higher level. Such a sequence suggests widespread destruction and systematic rebuilding.

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