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Highlights from the 13th Symposium of Byzantine Sigillography (Cologne, 27-29 March)

The participznts (March 28, 2025).

The symposium on Byzantine sigillography that concluded last week was both a testament to the excellent organization by the Department of Byzantine Studies at the University of Cologne and a vibrant space for high-quality presentations and engaging, fruitful discussions. Unlike previous editions, which were often by invitation only, this year’s symposium included a highly successful call for papers. This broader participation provided a unique opportunity to learn about numerous exciting projects and personal research efforts.

By examining roles such as the Count of the Stables and the Gerokomos, the conference shed light on certain functions of the central administration that clearly deserve renewed attention—thanks in large part to sigillographic contributions. This insight calls for a systematic reassessment of these administrative roles. The first section of the symposium also reminded us of the importance of integrating sigillographic sources with other written evidence. While seals frequently confirm known data, they can also contradict it—or at least offer alternative perspectives. Rather than yielding definitive answers, these divergences often spark new, productive questions. After all, every piece of research begins with a question.

The linguistic analysis of seal legends was another key theme. This type of analysis clarifies relationships between terms used to describe various functions—for example, the ek prosopou—and offers new insights into these roles. Perhaps more significantly, it challenges traditional notions of “errors” in seal legends, advocating instead for a conservative editorial approach. Rather than correcting these “mistakes,” emendations should be included in a critical apparatus and fully justified.

Seals from the Palaiologan period—often underrepresented in sigillographic studies—were a particularly welcome topic. Presentations explored statistical, prosopographical, and social approaches aimed at better understanding the aristocracy of the time. One presentation focused on the unique iconography of David of Trebizond, reflecting the issuer’s evolving self-representation in response to contemporary historical events.

The symposium also featured exciting new material from well-localized sites such as Rhodes, the Acropolis of Athens, Chios, and the area around Antioch of Pisidia. Given the frequent lack of provenance in sigillography, such finds are especially valuable, offering enhanced interpretive potential. Additional material presented during the “thematic” section included objects from Turkish museums and the Canellopoulos Collection—though unfortunately without detailed provenance information.

Understanding a seal’s origin—whether through its legend or findspot—opens up further interpretive possibilities. This kind of data allows researchers to explore seal circulation and the political, commercial, and geographic networks implied by their movement. Several symposium papers incorporated geographic data, examining interregional connections such as those between the western Black Sea and western Asia Minor, as well as more focused regional studies on areas like Thrace, Sardinia, and the Danube basin near Dorostolon.

Two other geographically distant but crucial regions of the empire—Italy and Africa in the 7th century—were also represented. One paper focused on seals that may be attributed to the Exarch Theodoros Kalliopas, while another examined the Praetorian Prefect Marinus, who also served as kommerkiarios.

The symposium underscored that seals are not isolated artifacts but are embedded in their cultural context. Their characteristics can be mirrored in other objects—an insight that helps us better understand both the seals and those related items. Rings, for instance, were reexamined in light of sigillographic and textual parallels, prompting a reevaluation of their interpretation in scholarly literature. Architecture offered another avenue: monograms, typical of seals, were found on buildings in Constantinople, suggesting that sigillographic practices could clarify their architectural usage. This comparative approach extended to signacula and markers, revealing affinities despite differences in matrices, legend complexity, or epigraphy. Broadening the scope of comparative material—across different object types and even cultures—enriches the field, offering not just points of contact but also valuable contrasts that inspire new, unexpected research questions.

No previous symposium on Byzantine sigillography—none of the twelve before it—has emphasized methodological innovation and publication strategies as strongly as this one. Digital tools were not a mere appendix to the event; they actively shaped its agenda (and helped fund it). Ignoring this shift is no longer an option.

The first day introduced the current version of the Taktikon, a promising prosopographical tool focused on specific social groups, primarily—but not exclusively—drawn from sigillographic sources. One of its standout features is the use of unique identifiers for seals and boulloteria.

Another ambitious initiative is the DigiSigiCorp project, centered on seals from Bulgaria. These often have well-documented findspots and histories, and the project highlights the value of such data through a digital lens.

The symposium also marked the official launch of the SigiDoc portal. SigiDoc is both a standard for digital scholarly editions of seals—developed by the DigiByzSeal project and used also by the DigiSigiCorp project—and the name of the portal itself. The naming reflects its established reputation among both sigillographers and digital humanists.

The creation of SigiDoc is not simply the result of technological maturity—it’s about will. Discussions around such tools began two decades ago. Now, the tools are functional, tested, and available to all. What’s needed is the willingness to adopt them, even if doing so requires a short period of adjustment. They are designed to be inclusive and user-friendly.

Moreover, the digital solutions presented at the symposium are far more sustainable than traditional print publications. While printed volumes are elegant and of high quality, they are economically and scientifically outdated—not to mention static and impossible to update. A striking example came during the symposium itself: an update to the Taktikon book (published in 2021) was presented, but the ideal home for such data would clearly be the forthcoming database. These updates also underscore the significance of seals sold via online auctions— not only for individual specimens of particular interest, but also as part of broader research requiring extensive surveying.

Importantly, SigiDoc and the infrastructure developed by DigiByzSeal aim far beyond individual corpora. What shapes a discipline is a large, shared corpus of reference material. Previous attempts to build such a resource have yielded valuable publications—but they never fully realized the goal. The issue isn’t expertise—it’s organization. This is not a job for a single scholar. It must be a collective effort, and the newly presented portal allows exactly that: to contribute while continuing the everyday work of studying and publishing Byzantine seals. Every contribution will remain clearly attributed—no one will become an anonymous data-entry assistant. The portal is not just a tool—it is, at present, the only viable path toward building le corpus des sceaux de l’Empire byzantin.

The portal also fosters a collaborative, active community. It’s especially well suited to manage the ever-growing body of seals sold through online auctions. Some researchers already gather selections of these, but individual efforts are no substitute for a systematic approach. Only collective action can prevent the loss of this critical material. Many already take notes on seals they find interesting—but the field needs more than private interest. From a technical and organizational standpoint, nothing prevents sigillographers from dividing up auction houses, monitoring a few each, and sharing their findings via the portal. Doing so would make the information instantly available, contribute to the growing corpus, and benefit the entire research community.

The symposium proceedings will be published in the Monographies series of the “Centre d’histoire et civilisation de Byzance” (Paris). Publication is scheduled for summer 2026.

RTI in Paris

In the framework of the ANR-DFG DigiByzSeal project, for the imaging of damaged seals the choice was made to use Reflectance Transformation Imaging (RTI), a photographic technique that enables the surface of an object to be captured and explored with greater precision by simulating different lighting conditions. This method combines a series of photographs taken under different lighting angles to create an interactive digital file, where the user can adjust the light to reveal details, textures and reliefs invisible under normal lighting. Between 26 and 28 November 2024, a brand new RTI device, acquired by the French part of the DigiByzSeal project, was put to work on the premises of the Centre d’Histoire et Civilisation de Byzance at the Institut des Civilisations (Collège de France, Paris). Marcel Schaeben, a member of the Cologne Center for eHumanities (CCeH), partner of the DigiByzSeal project, and a connoisseur, among other things, of RTI’s functioning, helped Alessio Sopracasa, the P.I. of DigiByzSeal in France, to install the equipment and trained him in its use.

The equipment in question consists of:

  • what is known as a dome, inside which 54 flash units are installed, each lighting up automatically at a preset speed: the seal is then placed under this dome, which is 15 cm high and has a base with a diameter of 30 cm; this dome was made by the company RTI Dome based in Paris;
  • a camera positioned above the dome, synchronised with the lighting of the dome’s flashes, taking 54 photos from 54 different angles of light impact: the choice was a Sony Alpha 7R V, with a Sony 90 mm macro;
  • a tripod to position the camera;
  • a computer to which the camera could transfer images in real time.

The kick-off took place in the ‘Catherine Piganiol room’ in the Byzantine Library of the Collège de France, where the equipment was laid out as shown in the following photo:

RTI dome, Paris
RTI Dome deployed in Paris for Byzantine seals for the first time (photo credits: Alessio Sopracasa).

In the next stage, the camera was first connected to the dome, whose control box can be seen here, and then to the computer:

The RTI Domme connected to the calera and to the compuer (photo credits: Alessio Sopracasa).

Once transferred to the computer, the images are reworked using the following software, in order

With the RTI Viewer the researcher can display and interact with RTI images: thanks to this technology, there is a greater chance of being able to read the inscriptions on damaged seals.

A few examples of different renderings on a same seal:

RTI Viewer: default mode (photo credits and seal: Alessio Sopracasa).
RTI Viewer: diffuse gain mode (photo credits and seal: Alessio Sopracasa).
RTI Viewer: specular enhancement mode (photo credits and seal: Alessio Sopracasa).
RTI Viewer: normals visualization mode (photo credits and seal: Alessio Sopracasa).

Further readings

  • M. Schaeben and M.T. Catalano, Byzantine Sigillography and RTI: Insights from the DigiByzSeal Project in Cologne, Digital Medievalist 2024 (forthcoming). DOI: https://doi.org/10.16995/dm.15117.
  • M.T. Catalano, Nutzen und Grenzen der RTI-Fotografie am Beispiel von zwei stark beschädigten byzantinischen Bleisiegeln Perspectives, Studies in Byzantine Sigillography 14 (2022), 147-157.
  • M.T. Catalano, M. Filosa, C. Sode, Byzantine Seals from the Robert Feind Collection in Cologne: Research and Publication in the Context of the Digital Humanities, Revue des études byzantines 79 (2021), 297–322. DOI: 10.2143/REB.79.0.3289649

Annonce : XIII International Symposium on Byzantine Seal Studies

Nous avons le plaisir de partager avec vous l’appel à communications pour l’International Symposium on Byzantine Seal Studies, qui aura lieu à l’Université de Cologne les 27 et 28 mars 2025.

Le symposium est organisé sous les auspices du projet ANR/DFG DigiByzSeal – Unlocking the Hidden Value of Seals: New Methodologies for Historical Research in Byzantine Studies et constituera l’événement de clôture de cette fructueuse coopération franco-allemande.

Sous le thème “Tradition andinnovation”, au sein du cadre de la sigillographie byzantine, nous explorerons divers sujets, y compris, mais sans s’y limiter :

  • l’étude de l’administration byzantine
  • la prosopographie
  • l’histoire sociale et l’identité
  • l’iconographie sur les sceaux byzantins
  • les aspects linguistiques des sceaux byzantins
  • les influences et les échanges interculturels dans la sigillographie byzantine
  • les approches numériques et les méthodologies innovantes dans l’étude des sceaux.

De plus amples informations, ainsi que le formulaire de proposition de communication, sont disponibles sur ce lien.

Pour toute question complémentaire, veuillez nous contacter à l’adresse suivante : siegel-symposium@uni-koeln.de.

Nous nous réjouissons de votre participation !

We are pleased to share with you the call for papers for the XIII International Symposium on Byzantine Seal Studies, which will take place at the University of Cologne in 27-28 of March 2025.

The Symposium is organized under the auspices of the ANR/DFG Project DigiByzSeal – Unlocking the Hidden Value of Seals: New Methodologies for Historical Research in Byzantine Studies and will represent the closing event of this fruitful French-German cooperation.

With the theme “Tradition and Innovation”, within the field of Byzantine Sigillography,

 we will explore various topics including but not limited to:


– the study of the Byzantine administration
– prosopography
– social history and identity
– imagery on Byzantine seals
– linguistic aspects of Byzantine seals
– cross-cultural influences and exchanges in Byzantine sigillography
– digital approaches and innovative methodologies in the study of seals

More information, as well as the submission form, can be found in this link.

For any further questions, please contact us at siegel-symposium@uni-koeln.de.

We are looking forward to hearing from you!

Sceau du mois de janvier (Paris)

Alors que le début de l’année 2024 bat son plein et que la France voit un renouvellement de l’équipe gouvernementale, nous pouvons nous plonger dans l’actualité politique byzantine de 1055. En effet, le 11 janvier de cette année, l’empereur Constantin IX Monomaque est décédé d’une pleurésie, contractée à la suite d’une baignade. Son agonie et sa mort ont contribué à relancer le débat sur l’identité de son successeur. La course au pouvoir impérial reprenait à Byzance …

Voici l’un des sceaux impériaux de Monomaque. Il s’agit d’une version classique des sceaux que cet empereur a fait frapper pour accompagner les missives portant ses ordres et les récompenses attribuées à ses fidèles. Le Christ n’étonne pas car il est le protecteur évident du basileus. Plus intéressante est l’iconographie de l’empereur lui-même. En effet, les traits sont encore personnalisés et la présentation en buste, qui disparaîtra peu après Constantin IX permet de distinguer assez clairement l’empereur de ses prédécesseurs et successeurs immédiats, même sans l’inscription indiquant son identité. D’ailleurs, sur les sceaux, Monomaque a uniquement conservé son prénom et son titre impérial en lettre latines et grecques : « Constantinos autocrator ». Contrairement à la monnaie, où l’empereur innovera en faisant figurer son nom de famille : « Monomachos ». A contrario les regalia présentés sont eux classiques : la chlamyde constellée de pierreries, le sceptre trifide, le globe crucigère.

Ce sceau a été retrouve dans l’ancien thème des Thracésiens, en Asie Mineure occidentale, une région avec laquelle l’empereur avait des liens, ou du moins avec une partie de ses élites aristocratiques et monastiques. L’empereur a pu envoyer une lettre à l’un de ses partisans ou à l’un des hommes saints de la région. Il est aussi tout à fait possible qu’il ait envoyé une lettre à un fonctionnaire civil ou à un officier de la province, puisque les Thracédiens étaient l’un des thèmes les plus riches et les plus importants de l’Empire.

Constantin IX Monomaque (empereur byzantin, 1042-1055)
Inv. : Tatış 2382. Provenance : Söke (basse vallée du Méandre).
Dia. : 34. Poids : 33,33 g. Ed. : Jean-Claude Cheynet

Sceau du mois : Novembre

Working on the project we came across a seal (SB-370) with a spectacular depiction of St. John the Theologian. The seal is broken into two halves, but well readable. The image on the obverse of the seal seems to be hitherto unattested on Byzantine seals: St. John the Theologian is shown holding a Gospel in his right hand and bending to the right. The legend on the reverse is also remarkable. The end of the legend is partly missing but can be restored with the help of a parallel seal auctioned by Roma Numismatics. It is a metrical legend that reads: Σκέπις ἐπιστίθιε ἠγαπημένε τὸν σὸν οἰκέτην Ὀρέστην Ἰωάννην („Protect, beloved epistethios, your servant John Orestes“). Identifying metrical seals, especially when they are not in perfect condition and lack parallels, poses a particular challenge. Metrical legends do not follow the same rules as other seals and can sometimes even feature false metrics. Taking into account the epigraphy and ligatures, a dating to the 13th century is suggested. The name of the seal owner John corresponds very well with the name of the saint depicted on the obverse, a usual phenomenon in sigillography as well as in numismatics, whereas the family name Orestes is attested from the 14th c. onwards. With regard to the dating of the seal to the 13th century this seal would therefore represent one of the earliest occurrences of Orestes as a family name.

If you like to get more information about this seal, see Catalano, Maria Teresa, Martina Filosa, and Claudia Sode. “Byzantine Seals from the Robert Feind Collection in Cologne: Research and Publication in the Context of the Digital Humanities.” Revue Des Études Byzantines 79 (2021): 297–322; here 307–309.

Photo: SB-370 Robert Feind Collection.

The seal has also undergone a lead isotope analysis; see:

–     Karagiorgou, Olga, Merkel, Stephen and Wołoszyn, Marcin. “A contribution to the technology and sources of lead in Byzantium: lead isotope analysis of ten Byzantine seals” Byzantinische Zeitschrift 114, no. 3 (2021): 1161-1203. https://doi.org/10.1515/bz-2021-0058.

Réunion d’équipe franco-allemande (Octobre 2023)

Nouvelle réunion des équipes française et allemande au cours du mois d’octobre (10-11 octobre 2023).

L’Université de Cologne a accueilli les membres de l’équipe française pour avancer sur les sujets techniques, numériques et de choix d’organisation des sceaux dans la version finale de SigiDoc.

Cette réunion a permis des avancées notables sur plusieurs questions qui restaient pendantes :

  • Réorganisation des listes d’autorité (fonctions, dignités, géographie),
  • Développer et améliorer les options de recherche pour trouver plus de liens entre les sceaux hébergés sur la plate-forme,
  • Choisir les objectifs concernant la prosopographie afin d’harmoniser les décisions pour éviter les doublons, voire favoriser les liens avec les bases de données prosopographiques byzantines en ligne,
  • Repenser et refondre la liste d’autorité iconographique qui posait des problèmes de présentation : finalement le tag « bubble » a été choisi après plusieurs discussions,
  • Favoriser l’harmonisation des présentations écrites entre les équipes française et allemande afin d’éviter des divergences d’écritures,
  • Et bien d’autres …

Le travail se poursuit pour SigiDoc et les nouveaux progrès seront sans aucun doute davantage substantiels au début de l’année 2024.

Sceau du mois de septembre (Cologne)

A key highlight of the program, facilitated by the use of Reflectance Transformation Imaging (RTI), is its ability to identify seals with significant damage that were previously impossible to read with the naked eye. An illustrative case is the seal SB-25 from the Robert Feind collection. Through our RTI images, the inscriptions became legible, leading us to discover a parallel in the Dumbarton Oaks collection: BZS.1958.106.4995. Here, we read the inscription as Ἅγνη, φύλατι δουκὶ Κων(σταντίνῳ) το Ὤπο (“Holy one, watch over the doux Konstantinos Opos”). Konstantinos Opos is a well-documented figure in historical sources, notably in Anna Comnene’s work. He held a significant position as an officer under Emperor Alexios I, actively participating in operations against the emir of Smyrna, Tzachas (1081 ‒ 1093), and compelling the crusader count Raoul to return to Asia. Additionally, he is recorded as a protoproedros in the  Council of Blachernai in 1094.

From the aforementioned seal, we glean that Konstantinos Opos, at a certain point in his career at the end of the 11th/ early 12th century, assumed the role of doux. According to V. Laurent, the term “doux” here signifies the military commander of a specific administrative region or “thema”. Notably, on numerous seals, the office is referenced independently, without the associated town or region where the officer served.

Photo: SB-25 Robert Feind Collection.

Photo: Pictures of SB-25 taken with RTI: Specular enhancement mode (l.) & Default mode (r.).

If you want to learn more about RTI, here you have some interesting papers:

–   Fischer, Franz, and Stephan Makowski. “Digitalisierung von Siegeln mittels Reflectance Transformation Imaging (RTI),” Paginae Historiae 25, no. 1 (2017): 137–41.

–    Catalano, Maria Teresa. “Nutzen Und Grenzen Der RTI-Fotografie Am Beispiel von Zwei Stark Beschädigten Byzantinischen Bleisiegeln.” Studies in Byzantine Sigillography 14 (2022): 147–57. https://doi.org/10.1484/M.SBS-EB.5.132253.-    Caine, Moshe, and Michael Magen. “Low Cost Heritage Imaging Techniques Compared.” BCS Learning & Development, 2017. https://doi.org/10.14236/ewic/EVA2017.85.

Who we are

Hi, our names are Pia and Sofia and we are the SigiDoc-encoders of the German team of DigiByzSeal! Let us introduce ourselves:

Pia: I am a master´s student in Byzantine Studies in Cologne, and I am very interested in Sigillography. I attended a few university courses on this topic and I realized how incredibly much information you can gain from little objects like seals. About DigiByzSeal I like the approach to connect Digital Humanities with the traditional methods of editing seals to ensure availability and sustainability of sigillographic data in the future.

Sofia: I am a Ph.D. candidate in Byzantine Archaeology at the Aristotle University of Thessaloniki and the University of Cologne. My research interests include Byzantine numismatics, economic history, and sigillography. Regarding the DigiByzSeal program, I found it fascinating and appealing to see how digital tools can be applied in Byzantine Studies and especially in Sigillography in order to make seal collections accessible to a wider audience and contribute to the creation of a comprehensive search corpus.

Hello, we are Sima Meziridou and Numa Buchs and we are the SigiDoc-encoders of the French team of DigiByzSeal. Here are some information about ourselves:

Sima: I am a post-doctoral researcher in the project and sigillography is a new horizon that I am exploring at the moment. As an archaeologist/historian, byzantine sigillography is a rather new field for me, allowing me to deepen my knowledge in byzantine political and social history. The DigiByzSeal project offers a necessary tool for byzantine studies and I am very excited to be part of it. 

Numa : I’m a post-doctoral student on the project and I’ve come into contact with sigillography during my research work, but this is the first time I’ve immersed myself in sigillography to this extent. As a historian of Byzantine history specialising in the army, administration and political history, this is a wonderful opportunity for me to develop my knowledge of this essential tool. I am extremely pleased to have joined the DigiByzSeal project.

Sceau du mois d’août (Paris)

En poursuivant le travail sur les sceaux au mois d’août, l’esprit vagabonde et voyage vers les plages chaudes et sablonneuses. Dans cette ambiance estivale, nous vous présentons un sceau qui nous a transporté de Paris à la Méditerranée.
Voici le sceau de Théophane, spathaire impérial et drongaire de la mer Egée, datant de la première moitié du IXe siècle, période d’apogée du thème. L’invocation du sceau est simple, Mère de Dieu aide, présentée sous forme de monogramme à l’avers, et le nom et les titres du propriétaire du sceau suivent au revers. À cette époque, être drongaire sur le thème de la mer Égée signifiait protéger et garantir l’autorité byzantine dans les îles, lutter contre la piraterie, intercepter les raids arabes provenant de Crète et veiller à l’équipement et à l’entretien des navires. D’où la courte prière à la Vierge, pour qu’elle aide et protège. Cependant, voyager dans toute la mer Égée et débarquer dans les ports de ces magnifiques îles devait aussi avoir ses avantages !

Photo: Cheynet, J. C. (2019), Les sceaux byzantins de la collection Yavuz Tatış, Buca, İzmir, p. 142.

Photo: Cheynet, J. C. (2019), Les sceaux byzantins de la collection Yavuz Tatış, Buca, İzmir, p. 142.

Réunion des équipes SigiDoc

Opération rassemblement pour l’équipe du projet SigiDoc ! Les membres des team française (Paris) et allemande (Cologne) ont pu bénéficier de l’accueil de l’École française de Rome pour se réunir du 12 au 13 mai.

Objectifs :

–        Etablir le planning des prochaines rencontres

–        Resserrer les liens entre les deux équipes

–        Trouver des idées aux problèmes sigillographiques posés par certains sceaux

–        Améliorer les outils pour l’encodage et la présentation des sceaux dans SigiDoc

Le travail a bien avancé mais il continue …