Stefano Costa

Tag: ancientceramics

  • GQB 2015, day 7: Gortyna in the 8th century through a ceramic lens

    GQB 2015, day 7: Gortyna in the 8th century through a ceramic lens

    On 16th July we’re headed to Rethymno for a workshop on Byzantine cities in Crete. Our participation was a last minute deal but I thought it would be useful to provide an overview on the entire city of Gortys, not limited to the GQB area, from the point of view of a ceramic specialist. What follows is a short summary of my talk. Tomorrow I will post a summary of the workshop and some conclusions about my own talk.

    At Gortys, there is a recognisable occupation phase in the 8th century: we have evidence in the Pretorio, the Byzantine Houses and the Byzantine Quarter, the Pythion, the Mitropolis basilica, the Agora, possibly the Acropolis and even some rural sites such as the small farm of Orthipetra in the Mitropolianos valley and Chalara near Festos. In short, almost everywhere we’ve been excavating in the past 20 years we found evidence later than the 7th century, even without accounting for the prolonged use of some ceramic items.

    Therefore our research question should not be whether the city is still alive in the 8th century but how we understand the life in Gortys by means of archaeological indicators such as ceramic finds.

    In the past few years, we have collectively published ceramic and numismatic evidence that contradicts the traditional date of 670 AD for an earthquake – pushing some 50-60 years later a possible catastrophic event (some publications are shy about this, though). When we speak of the 8th century in Gortys it is useful to distinguish into a “long 7th century” that lasts until this event and the remaining decades of the 8th century, according to both the ceramic and numismatic evidence. The period after this event is usually mentioned as “VIII e IX secolo” mainly because we have to accomodate for the 826-829 AD date from the written sources about the “Arab” conquest of Crete. I’ll leave a discussion of the 9th century for a next occasion, but the same approach can be used.

    Part of our issues with the 8th century derive from the impact that earlier works like Gortina II or Gortina V had on the following studies, with their typological approach. It is only recently that we have collectively started focusing on contexts as atomic units of study, at least in some cases.

    The main ceramic indicators we have are:

    • Globular amphorae
    • Sovradipinta bizantina
    • Late Mediterranean fine wares
    • Cooking wares
    • Glazed wares
    • Chafing dishes
    • Oil lamps

    Urban areas

    The Pretorio, Byzantine Houses, Byzantine Quarter and Pythion are best considered as a single area, that had its main focus on the “Strada Nord” which crossed the urban area. Lots of excavations here!

    The Mitropolis basilica is the most important religious area of the city. Recent excavations on the outer part of the absidal area have given important evidence.

    The Agora was excavated in the 1990s but only recently published. Apart from a significant amount of Medieval material, including Byzantine amphorae, there is a deposit (“C”) dated from this period, possibly from the same destructive event seen elsewhere in Gortys.

    The Acropolis was excavated in the 1960s and saw only a small intervention in 2003. It took a few decades to realise that some of the decorated pottery identified as Minoan was in fact Byzantine. Without a reevaluation of the material, we are left with a weak basis to analyse the place that must have been the seat of the civil/military power from the late 7th to the 9th century, and only the occupation is certain, with architectural remains and at least one coin.

    Main ceramic indicators

    Globular amphorae are well known but on their own they provide little chronological detail. However, their recurring association with other indicators that have a more tight chronology is very interesting. Their source is commonly indicated as either Cretan or Aegean: we still lack a precise indication in this regard. Their abundance in this period all around Gortys, unparalleled by other amphora types, indicates that they were used primarily as a storage container, to stockpile liquids (wine?) in huge quantities – as much as 750 liters just in one building. Other amphorae that are quite numerous in this period are LRA 5/6 from Palestine and the Nile Delta region, and the LRA7 in some areas of the city.

    The Sovradipinta bizantina is of limited interest as a general indicator for Crete, because it only circulates in the immediate vicinity of Gortys and only rarely found outside the Mesara. Its production starts at the end of the 6th century and goes on into the 7th and 8th century, apparently without any significant distinction in typology or decoration. Again, it is difficult to use this indicator alone to point to an 8th century date, even though ceramic evidence from the Praetorium points to a different chronology, mostly in the late 7th and 8th century. One thing is sure: the Sovradipinta bizantina was never meant to be a replacement for missing imports, since most of it is on closed forms like drinking cups, jugs, etc. that do not occur in the imported fine wares. Rather, we see decoration occurring on the formal repertoire of the local plain wares.

    Traditionally, the end of trade in Mediterranean fine wares is dated at the end of the 7th century, to coincide at the very last with the Arab conquest of Carthage in 698. However, several authors agree that some productions could continue to be exported for some time in the 8th century, such as:

    • the late African Red Slip D3 / D4, form 107 and 109 described by Bonifay;
    • Late Roman D / Cypriot Red Slip, form 9B described by Watson;
    • Egyptian Red Slip wares? We seem to have a consistent presence of Aswan ware, a production that is little known outside Egypt and is dated to to 7th century.

    In general, cooking pots of this period are frequently bag-shaped, in coarser, more fragile fabrics. Cooking pots made on the slow-wheel appear sporadically, like a paradigmatic example of simplified ceramic production or even a comeback of domestic modes of production – at the same time they challenge our stereotyped view of pottery as typology and require a technological study that goes beyond traditional archaeometric provenance analysis. It is difficult to tell whether there were different cooking habits since most publications lack the level of detail that is needed, such as which parts of the cooking pot have traces of fire exposure, which have traces of dipper / κουτάλα, etc.

    Glazed wares (the “Glazed White Ware” series 1) are the most recognisable finds of the period. While the coarser glazed cooking pots date already from the mid-7th in Constantinople, their fine counterparts seem slightly later according to the studies of Hayes. Some 9th century examples were already known since the 1980s in Gortys, but recently we have been finding more examples including the beautiful 8th century chafing dish decorated with fish and palm tree. Other known examples from Crete are from Pseira and Itanos. They could be interpreted as luxury items, but as with the imported wares we should be cautious to make an equation between archaeological rarity and actual social/economic value, since this production is very rare all over the Byzantine Empire.

    Chafing dishes / σαλτσάρια come also in coarse fabrics, at least in two separate contexts from the BQ and the Agora. Since we have so few examples of this type, it is useful to see that the culinary habits linked to this new type of cooking vessel are not limited to glazed dishes (that could easily be gifts or decorative items). There’s room for discussing the fact that this habit appears in Gortys at the same time as other important centres of the Byzantine Empire, with simplistic explanations like the military or new civil authorities.

    Finally, oil lamps. The “juglet” lamps are well known, especially type I. It seems that type II could be more widespread in the later period. Lamps in this period are less standardised, but in Gortys we don’t see hand-made lamps of the simpler open types. A separate discussion is needed to take into account the impact of glass on lighting of interior spaces, and we still don’t have collected the necessary data from our excavated material.

    Conclusions

    I’d like to leave my conclusions blank for tomorrow’s post.

    The cover image is an African Red Slip sherd, form Hayes 109B, in D3 fabric, photographed through a magnifying lens (GQB CER 746.2).

  • GQB 2015, day 5: substitute

    GQB 2015, day 5: substitute

    I’m a substitute for another guy
    I look pretty tall but my heels are high

    As I mentioned the other day, our team is in Gortys at the same time with the University of Padua team directed by Jacopo Bonetto. Since there is no ceramic specialist with them this year, they asked me to take a look at a few ceramic contexts from the Late Antique phase of the temple of Apollo (Ναός Απόλλωνος) where they excavated a few explorative trenches last year. This is what is normally called spot-dating: have a quick look at diagnostic finds from a context, identify whether there is enough material to provide a significant chronology and output a date range. Usually it is difficult to be very precise with less than 20-30 diagnostic finds, especially with local wares, and “first half of the sixth century AD” is good enough a starting point. Another recurring issue is with residual material, that is the norm in Mediterranean urban sites because small scraps of pottery as always found in the soil, sometimes centuries older than the date of formation. Residuality is an interesting phenomenon, too often overlooked or “analysed” in simplistic terms because it is rather difficult to model.

    In detail, I’ve been looking at 5 contexts dated from the 3rd to the 6th century. The later ones are slightly larger and can be dated pretty reliably:

    • in the mid-6th century you get African Red Slip Hayes 104A and LRC/Phocaean Red Slip Hayes 10A together with Aegean cooking wares;
    • in the 5th century the most recognisable finds are local basins with a painted zig-zag decoration on the rim, a few sherds of Late Roman Amphora 3 and African Keay 25
    • the earlier contexts are smaller, and more difficult to pinpoint with 1-2 diagnostic finds, either African Red Slip from the 4th century or Eastern Sigillata A from the early 2nd century.

    All these are floor assemblages, resulting from prolonged use on top of landfills: the difference, in theory, is that a landfill should be dated to a single moment in time and can contain earlier material, while the floor deposit will contain small pieces subject to trampling and walking, ideally from the period when the floor was in use. This distinction is useful in theory but in practice floor surfaces tend to be slightly over-excavated and the finds are all from top part of the lower fill layer.

    Archaeological map of Gortys: the bright areas are recent excavations with 8th century material; blue spot is the Pythion, orange spot the Byzantine Quarter.
    Archaeological map of Gortys: the bright areas are recent excavations with 8th century material; blue spot is the Pythion, orange spot the Byzantine Quarter.

    To my surprise, there were some beautiful and much larger assemblages from the 7th and 8th century that didn’t interest much to our colleagues from Padua, but were rather sweet for us Byzantine archaeologists! Apart from a very good selection of type-finds (Late Roman D/Cypriot Red Slip Hayes 9, juglet-shaped oil lamps, globular amphorae and their sibling water jars with one handle, Egyptian Red Slip dishes, cooking pots made on the slow wheel, etc) the context as a whole was both tremendously familiar and interesting, so similar to what we found in the nearby Byzantine Quarter / Βυζαντινή Συνοικία. The difference is in the BQ we see traces of people dwelling well into the 8th century, while houses in the Pythion area seem abandoned slightly earlier, thus we might be looking at glorious rubbish dumps from “our” side. It is truly worth a further look.

  • GQB 2015, day 4: the people must have something good to read

    GQB 2015, day 4: the people must have something good to read

    The people must have something good to read on a Sunday

    With only ten days of fieldwork, weekends are a social convention that is left for another time, and the alarm is only marginally generous at 8 o’clock.

    As anticipated two days ago, my main task here is to finalise the study of ceramic contexts towards publication. Today I made a few steps in a good direction, with a convincing draft for a “layout” of each context, where various types of information are shown as an introductory summary:

    • a small stratigraphic diagram
    • an excavation plan with the position of the context under examination
    • a photograph of the context during excavation
    • a photograph of all ceramic finds from the context in a single view
    • three plots with the statistical distribution of:
      • sherd weight, that is not very useful without a reference value, but I still need to iterate on this
      • rim percentage as estimated vessel equivalent (eve)
      • chronology-weighted-by-eve, that is particularly useful for looking at residuality and depositional histories

    I’d like to add another infobox with a summary view of all objects that I identified as part of the systemic context (cutting short on the topic, for now), not as they were found but as they could have been while in use.

    Then an extended discussion follows, in a more “traditional” fashion, where the stratigraphic data and the contextual relationships are taken into account. My aim in this part is to bridge the information and the “hard data” from the stratigraphic analysis with a broader view on the life of the household, for example looking at various rooms and our interpretation of their function/use.

    After the discussion, a catalogue of all finds follows, with drawings/pictures that I will try to keep within the text or very close to their descriptive entries, avoiding separate “plates”, that would betray the principle of primacy of context that I’m following.

    There was some discussion about whether to include residual finds or not in this catalogue, with Enrico Zanini finally winning the argument thanks to a subtle distinction between residues and residuality. Only the latter should be discussed, leaving an extended description of residual finds to a separate section.

    I’m quite satisfied with this draft, at least on a conceptual level, but it definitely needs more work on a visual level.

  • Archaeology and Django: mind your jargon

    I have been writing small Django apps for archaeology since 2009 ‒ Django 1.0 had been released a few months earlier. I love Django as a programming framework: my initial choice was based on the ORM, at that time the only geo-enabled ORM that could be used out of the box, and years later GeoDjango still rocks. I almost immediately found out that the admin interface was a huge game-changer: instead of wasting weeks writing boilerplate CRUD, I could just focus on adding actual content and developing the frontend. Having your data model as source code (under version control) is the right thing for me and I cannot go back to using “database” programs like Access, FileMaker or LibreOffice.

    Previous work with Django in archaeology

    There is some prior art on using Django in the magic field of archaeology, this is what I got from published literature in the field of computer applications in archaeology:

    I have been discussing this interaction with Diego Gnesi Bartolani for some time now and he is developing another Django app. Python programming skills are becoming more common among archaeologists and it is not surprising that databases big and small are moving away from desktop-based solutions to web-based

    The ceramicist’s jargon

    There is one big problem with Django as a tool for archaeological data management: language. Here are some words that are either Python reserved keywords or very important in Django:

    • class (Python keyword)
    • type (Python keyword)
    • object (Python keyword)
    • form (HTML element, Django module)
    • site (Django contrib app)

    Unfortunately, these words are not only generic enough to be used in everyday speak, but they are very common in the archaeologist’s jargon, especially for ceramicists.

    Class is often used to describe a generic and wide group of objects, e.g. “amphorae”, “fine ware”, “lamps”, ”cooking ware” are classes of ceramic products ‒ i.e. categories. Sometimes class is also used for narrower categories such as “terra sigillata italica”, but the most accepted term in that case is ware. The definition of ware is ambiguous, and it can be based on several different criteria: chemical/geological analysis of source material; visible characteristics such as paint, decoration, manufacturing; typology. The upside is that ware has no meaning in either Python or Django.

    Form and type are both used within typologies. There are contrasting uses of these two terms:

    •  a form defines a broad category, tightly linked to function (e.g. dish, drinking cup, hydria, cythera) and a type defines a very specific instance of that form (e.g. Dragendorff 29); sub-types are allowed and this is in my experience the most widespread terminology;
    • a form is a specific instance of a broader function-based category ‒ this terminology is used by John W. Hayes in his Late Roman Pottery.

    These terminology problems, regardless of their cause, are complicated by translation from one language to another, and regional/local traditions. Wikipedia has a short but useful description of the general issues of ceramic typology at the Type (archaeology) page.

    Site is perhaps the best understood source of confusion, and the less problematic. First of all everyone knows that the word site can have a lots of meanings and lots of archaeologists survive using both the website and the archaeological site meaning everyday. Secondly, even though the sites app is included by default in Django, it is not so ubiquitous ‒ I always used it only when deploying, una tantum.

    Object is a generic word. Shame on every programming language designer who ever thought it was a good idea to use such a generic word in a programming language, eventually polluting natural language in this digital age. No matter how strongly you think object is a good term to designate archaeological finds, items, artifacts, features, layers, deposits and so on, thou shalt not use object when creating database fields, programming functions, visualisation interfaces or anything else, really.

    The horror is when you end up writing code like this:

    class Class(models.Model)
    '''A class. Both a Python class and a classification category.'''

    pass

class Type(models.Model)
    '''A type. Actually, a Python class.

    >>> t = Type()
    >>> type(t)
    <class '__main__.Type'>
    '''

    Not nice.

    Is there a solution to this mess? Yes. As any serious Pythonista knows…

    Explicit is better than implicit.
    […]
    Namespaces are one honking great idea — let’s do more of those!

    The Zen of Python

    Since changing the Python syntax is not a great idea, the best solution is to prefix anything potentially ambiguous to make it explicit (as suggested by the honking idea of namespaces ‒ a prefix is a poor man’s namespace). If you follow this, or a likewise approach, you won’t be left wondering if that form is an HTML form or a category of ceramic items.

    # pseudo-models.py

class CeramicClass(models.Model):
    '''A wide category of ceramic items, comprising many forms.'''

    name = models.CharField()

class CeramicForm(models.Model):
    '''A ceramic form. Totally different from CeramicType.'''

    name = models.CharField()

class CeramicType(models.Model):
    '''A ceramic type. Whatever that means.'''

    name = models.CharField()
    ceramic_class = models.ForeignKey(CeramicClass)
    ceramic_form = models.ForeignKey(CeramicForm)
    source_ref = models.URLField()

class ArcheoSite(models.Model):
    '''A friendly, muddy, rotting archaeological site.'''

    name = models.CharField()

class CeramicFind(models.Model):
    '''The real thing you can touch and look at.'''

    ceramic_type = models.ForeignKey(CeramicType)
    archeo_site = models.ForeignKey(ArcheoSite)
    ... # billions of other fields

  • Amsterdam, here I come

    The excavation campaign in Vignale is over, and a new season of study and research is just beginning for me. The next 12 months are the last year of my doctorate. To get a wider picture of ceramic studies beyond the traditional chronological limits of Late Antiquity (or, to put it more smartly, to follow Peter Brown’s own definition of it), I’m heading to Amsterdam today for a 3-days conference on “Fact and fiction in medieval and post-medieval ceramics in the Eastern Mediterranean”, organised at UvA by Dr. Joanita Vroom.

    As usual, I will share my notes from the conference on a shared notepad (here).

    By the way, this is the reason why I’m not going to Open Government Data Camp in Warsaw. Good luck to all the friends there!

  • Byzantine and Christian Museum of Athens: the pottery on display

    I had a chance to spend two entire weeks in Athens last November. Apart from studying at the Italian, British and American libraries, I also visited the Byzantine and Christian Museum, that has a good collection of Early Byzantine pottery and silverware. The collection was noted by Sebastian Heath, who used to keep a review of such resources on one of his blogs.

    Silver tableware

    Lamps

    Amphorae

    Saint Menas pilgrim flasks

    African Red Slip Ware, Hayes 104 large dish

    Kitchen and tableware

    Coins

    Glass and ceramic unguentaria

    Late Roman jugs and lamps from the Panepistimio metro station

  • Museo archeologico di Portoferraio

    Il museo civico archeologico di Portoferraio ospita reperti provenienti da tutta l’isola d’Elba e da alcuni relitti delle acque circostanti.

    Ceramica romana di età repubblicana nelle vetrine del museo

    Fortunatamente è stato possibile scattare fotografie all’interno, anche se naturalmente la qualità non è molto buona. Purtroppo non esiste un catalogo, anche se il materiale è in gran parte pubblicato.

    Scavando a Vignale, un sito di età romana di fronte all’isola d’Elba, la visita era in qualche modo un dovere. La collezione di ceramiche ellenistiche e romane è ampia: sono particolarmente interessanti i rinvenimenti subacquei e quelli degli scavi nelle villae maritimae dell’isola, come la villa delle Grotte.