History of the research
In Greece there is a large number of churches of the Middle and Late Byzantine period, as well as of the early modern era, which are decorated on their façades with glazed open vessels (usually plates and bowls). They are properly immured in special receptacles in the masonry of the monuments. These clay vessels constitute one of the forms of colorful decoration  of the façades of the Byzantine churches. They were originally made for everyday use, and in this case they acquired a second, other than their prime, use. The latter brings out their decorative value, as only glazed vessels, usually decorated, are selected to be immured in the façades of the monuments.
Although this form of decoration was identified very early by scholars of Byzantine architecture , with the earliest references already occurring at the first half of the 20th century by G. Millet, A. Grabar, A.H.S. Megaw and G. Sotiriou, what mainly concerned the research was the origin of this type of decoration and the role of the immured vessels in the façades of the churches, as part of the architectural ensemble. Typical, in respect to the first case, are the views of G. Millet, A. Grabar and H. Bouras , while, in respect to the second case, detailed annotations of the subject by G. Velenis and K. Tsouris stand out, on the occasion of their wider, detailed studies on the exterior adornment of the ceramic decoration of the monuments of Byzantine architecture, respectively. On the contrary, there is hardly any studies dealing thoroughly solely with immured ceramics themselves. We mention characteristically those by A.H.S. Megaw, G. Nikolakopoulos, H. Philon, G.D.R. Sanders and K. Tsouris. However most of them deal with isolated cases of monuments and up to this moment there are not any composite studies to engage collectively with glazed vessels of one or more regions. In this respect, the study of K. Tsouris about those churches of the Northwestern Greece where the relative decoration form is located, remained until recently an isolated case. The few and regularly published studies of G. Nikolakopoulos during 1979-1988 for the immured vessels of separate monuments of the prefectures of Attica and Argolis –though indicating the beginning of a systematic effort to deal with this subject and with obvious interest to give prominence equally to the role of clay pots on each side of the monument and to the type of each object separately– did not lead to a systematic investigation.
In Italy, by contrast, where this kind of exterior decoration of churches occurs very often, there are numerous studies and systematic publications, mainly from the 1970s onwards, which adopted the term bacini to identify the open vessels that are immured on the façades of the churches. Notable is the pioneer, composite study of G. Berti and L. Tongiorgi on the immured vessels in churches of Pisa. At the same time, other scholars have been involved with the immured vessels of monuments in the Italian peninsula, such as H. Blake, S. Gelichi, S. Nepoti. The momentum created by the study on bacini of the Pisa region is reflected in the numerous studies cited by G. Berti and E. Tongiorgi and, more recently, in the proceedings of a conference dedicated exclusively to the research of immured vessels. The doctoral thesis of M. Hobart for the churches of Sardinia, where some immured vessels are located, is another recent example of the systematic investigation of the spread of this form of decoration in a wide area rather than simply identifying it in individual monuments. It is worth noting that at the time of the late Middle Ages, in the eastern Mediterranean basin, a corresponding practice of immured glazed pottery in the façades of monuments occurs in several parts of Asia Minor and Egypt. Moreover, Russian churches of the same era bear examples of the same practice. The case of the immured glazed pottery in the interior of Post-Byzantine churches of Cyprus remains exemplary.
All the aforementioned studies have shown the importance of dealing with this issue, as the study of immured vessels offers important information not only in the study of medieval glazed pottery and in solving problems related to the dating of the monument in which they are immured, but also in the history of the region. Alongside it raises interesting questions regarding the purpose or purposes served by the immuring of vessels.
In this wider context the systematic address of the issue initiated. Its investigation was prompt by a collaboration with the programme «Western Art in Crete» of the Institute of Mediterranean Studies, and O. Gratziou, on the identification of the types of vessels that adorn the church of Zoodochos Pigi in Prinos in the Mylopotamos region. Seeking comparative material for them, the façades of more churches of the island were investigated. From this preliminary indexing became clear that numerous churches of Crete are decorated externally with immured open vessels, despite the fact that this region was not included by previous researches in those where the practice is located, even if G. Gerola noted, since early 20th century, the existence of immured vessels in churches of the island. Through the concentration of the relevant material it became understood that only the overall investigation of the matter could lead to more reliable observations on these issues and to a better understanding of the diffusion of the immured vessels’ practice, rather than the fragmentation of research on separate, individual churches or to a single region. Thus emerged the research programme «Immured vessels in churches of Greece: an online corpus» which is hosted, with the approval of the Director of Research of Ι.Η.R. Dr. Anna Lambropoulou, in the broader programme of the Institute «Historical Geography of the Helladic Region».
Originally, given that the first information about churches with immured vessels in Greece came from churches of Attica and the Peloponnese, the programme is limited to the detailed recording in a common database of the relevant data of these areas, read in conjunction with those resulting from the immured vessels in churches of Crete. Already the registered churches are more than 200 with the most populous sample being located in Crete. The data already published for the churches of Northwestern Greece, which are also decorated with immured vessels, will be compared with this sample. It has already been planned to extend the relevant research to other areas of Greece, such as Central and Northern Greece and the Aegean islands, where churches with immured vessels have been located.
Access to the database is at present limited to partner members only.
Anastasia G. Yangaki
Androudis 2007: P. Androudis, «Ο ναός της Κοίμησης της Θεοτόκου στην Επισκοπή Άνω Βόλου και ο εντοιχισμένος γλυπτός του διάκοσμος», ΔΧΑΕ per. Δ΄, vol. ΚΗ΄ (2007), 85-98.
Atti 1996: Atti XXVI Convegno Internaznionale della Ceramica, “I Bacini murati medievali. Problemi e stato della ricerca”, Albisola, 28-30 maggio 1993, Firenze 1996.
Βeliaev 2007: L. A. Beliaev, «Bacini: glazed househould pottery in Late Byzantine architecture» [στα ρώσικα], Rossiiskaya arkheologiya 3 (2007), 133-140.
Berti 1992: G. Berti, «Bacini ceramici e strutture architettoniche medievali. Considerazioni basate su una ricerca in Toscana», in: Atti del I Colloquio Hispano-italiano di archeologia medievale (Granada, Aprile 1990), Granada 1992, 133-172.
Berti 1996: G. Berti, «II. Problematiche relative allo studio dei “Bacini”», in: S. Gelichi, G. Berti, S. Nepoti, «Relazione introduttiva sui “Bacini”», in: Atti XXVI Convegno Internaznionale della Ceramica, “I Bacini murati medievali. Problemi e stato della ricerca”, Albisola, 28-30 maggio 1993, Firenze 1996, 9-20.
Berti, Gelichi 1993: G. Berti, S. Gelichi, «La ceramica bizantina nelle architetture dell’Italia medievale», in: S. Gelichi (ed.), La Ceramica nel mondo Bizantino tra XI e XV secolo e i suoi rapporti con l’Italia, Siena-Pontignano 11-13 Marzo 1991, Firenze, 1993, 125-199.
Berti, Giorgio 2011: G. Berti, M. Giorgio, Ceramiche con coperture vetrificate usate come “bacini”. Importazioni a Pisa e in altri centri della Toscana tra fine X e XIII secolo, Firenze 2011.
Berti, Tongiorgi 1981: G.Berti, L. Tongiorgi, I bacini ceramici medievali delle chiese di Pisa, Roma 1981.
Berti, Tongiorgi 1983: G. Berti, E. Tongiorgi, «Per lo studio dei bacini delle chiese di Pisa: Rassegna di recenti contributi alla storia della ceramica», in: Le ceramiche medievali delle chiese di Pisa. Contributo per una migliore comprensione delle loro caratteristiche del loro significato quale documento di storia, Pisa 1983, 37-79.
Blake 1980: Blake H., «The bacini of North Italy», in: La Céramique Médiévale en Méditerranée occidentale, X-XVe siècles, Valbonne 11-14 Septembre 1978, Paris 1980, 93-111.
Blake, Nepoti 1984: H. Blake, S. Nepoti, «I Bacini di S. Nicolo di Ravenna e la ceramica graffita medievale nell” Emilia-Romagna», Faenza 70 (1984), 354-368.
Bouras 1965: Ch. Bouras, Βυζαντινά σταυροθόλια με νευρώσεις, Αthen 1965.
Bouras 1994: Ch. Bouras, Ιστορία της Αρχιτεκτονικής, Δεύτερος τόμος, Αρχιτεκτονική στο Βυζάντιο, το Ισλάμ και την Δυτική Ευρώπη κατά τον Μεσαίωνα, Αthens 1994.
Castelletti 1994: L. Castelletti, «L’inserimento di ceramiche nell’architettura. Il caso della chiesa di San Romano a Lucca», Archeologia Medievale 21 (1994), 193-211.
Gerola 1993: G. Gerola, Βενετικά Μνημεία της Κρήτης (Εκκλησίες), transl. S. G. Spanakis, Crete 1993.
Grabar 1928: A. Grabar, Recherches sur les influences orientales dans l’art balkanique, Paris 1928.
Hadjikyriakos 2006: Ι. Hadjikyriakos, «La Decorazione Ceramica degli Interni Nelle Chiese di Cipro», RDAC (2006), 389-405.
Hobart 2006: Μ. Hobart, Sardinian Medieval Churches and Their Bacini: Architecture Embedded with Archeology, Ph.D. Dissertation, New York University 2006.
Megaw 1930-1931: Α. H. S. Megaw, «The Chronology of Some Middle Byzantine Churches», BSA 32 (1931-1932), 90-130.
Megaw 1964-1965: A. H. S. Megaw, «Glazed Bowls in Byzantine Churches», ΔΧΑΕ per. Δ΄, vol. Δ΄ (1964-1965), 145-162.
Νικολακόπουλος 1978: Γ. Νικολακόπουλος, Εντοιχισμένα κεραμεικά στις όψεις των μεσαιωνικών και επί τουρκοκρατίας εκκλησιών μας, Ι. Εισαγωγή, ΙΙ. Τα κεραμεικά των Αγίων Θεοδώρων, Αθήναι 1978.
Nikolakopoulos 1979: G. Nikolakopoulos, Εντοιχισμένα κεραμεικά στις όψεις των μεσαιωνικών και επί τουρκοκρατίας εκκλησιών μας, ΙΙΙ. Τα κεραμεικά της Παναγίας του Μέρμπακα της Ναυπλίας, Athens 1979.
Nikolakopoulos 1980: G. Nikolakopoulos, Εντοιχισμένα κεραμεικά στις όψεις των μεσαιωνικών και επί τουρκοκρατίας εκκλησιών μας, ΙV. Τα κεραμεικά του Καθολικού της Παναγίας Φανερωμένης της Σαλαμίνος, Athens 1980.
Nikolakopoulos 1988: G. Α. Nikolakopoulos, «Τα κεραμικά του παρεκκλησίου της Φανερωμένης της Σαλαμίνας», Αρχαιολογία 28 (1988), 81-84.
Nikolakopoulos 1989: G. Nikolakopoulos, «Εντοιχισμένα κεραμικά εκκλησιών», Αρχαιολογία 33 (1988), 66-71.
Philon 1985: Η. Philon, «Thessaloniki, Andalusia and the Golden Horde», Balkan Studies 26 (1985), 299-320.
Sanders 1989: G. D. R.Sanders, «Three Peloponnesian Churches and their importance for the Chronology of Late 13th and Early 14th century pottery in the Eastern Mediterranean», in: V. Déroche, J.M. Spieser (eds.), Recherches sur la céramique byzantine, BCH suppl. XVIII (Paris – Athènes 1989),189-199.
Sotiriou 1942: G. A. Sotiriou, Χριστιανική και βυζαντινή αρχαιολογία, τόμος Α΄, Χριστιανικά κοιμητήρια, Εκκλησιαστική αρχιτεκτονική, Athens 1942.
Tsouris 1988: Κ. Tsouris, Ο κεραμοπλαστικός διάκοσμος των υστεροβυζαντινών μνημείων της βορειοδυτικής Ελλάδος, Διδακτορική διατριβή, Kavala 1988.
Τsouris 1996: K. Tsouris, «Glazed Bowls in the Late Byzantine Churches of North-Western Greece», Archeologia Medievale 23 (1996), 603-624.
Tsouris 1998: K. Tsouris, «A Bowl Embedded in the Wall of the Chapel of the Hagioi Anargyroi in Vatopedi Monastery», Balkan Studies 39 (1998), 5-14.
Velenis 1984: G. M. Velenis, Ερμηνεία του εξωτερικού διακόσμου στη Βυζαντινή αρχιτεκτονική, (Διδακτορική διατριβή), Thessalonike 1984.
Yangaki 2010: A. G. Yangaki, «Εντοιχισμένα πινάκια σε εκκλησίες της Κρήτης: μια ερευνητική πρόταση», in: Μ. Andrianakis, Ι. Tzachili (ed.), Αρχαιολογικό Έργο Κρήτης 1, Πρακτικά της 1ης συνάντησης, Ρέθυμνο, 28-30 Νοεμβρίου 2008, Rethymnon 2010, 827-840.
Yangaki 2013: A. G. Yangaki, «Immured vessels in churches on Crete: Preliminary observations on material from the prefecture of Rethymnon», ΔΧΑΕ per Δ΄, vol. ΛΔ΄ (2013), 375-384.
 Indicatively, for a first cataloging of these, see Tsouris 1996, 620-621.
 For the technique and the ways of immuring vessels in churches, see Nikolakopoulos 1978, 17-19, fig. 7 – fig. 11.
 For other forms of external decoration see Tsouris 1996, 603 (where the relevant literature).
 Bouras 1965, 73 note 318; Velenis 1984, 194, 195 note 1, 267, 270; Bouras 1994, 230.
 Millet 1916, 283, fig. 106, fig. 118; Grabar 1928, 37; Megaw 1930, 90-130 passim; Sotiriou 1942, 411.
 See indicatively: Millet 1916, 283, fig. 106, fig. 118; Grabar 1928, 37-42, 51; Bouras 1965, 73 note 318.
 See respectively: Velenis 1984, 194, 267-270; Tsouris 1988, 95-116; Tsouris 1996, 603-619.
 Megaw 1964-1965, 145-162; Nikolakopoulos 1978; Nikolakopoulos 1979; Nikolakopoulos 1980; Nikolakopoulos 1988, 81-84; Nikolakopoulos 1989, 66-71; Philon 1985, 299-320; Sanders 1989, 189-199; Tsouris 1996, 603-624; Tsouris 1998, 5-14.
 Tsouris 1996, 603-624.
 Nikolakopoulos 1978; Nikolakopoulos 1979; Nikolakopoulos 1980; Nikolakopoulos 1988, 81-84; Nikolakopoulos 1989, 66-71.
 For the first reference to the term see Berti, Tongiorgi 1981, 9, note 1 and Berti, Tongiorgi 1983, 39 (where the relevant literature).
 Berti, Tongiorgi 1981. For an updated presentation of this material, Berti, Giorgio 2011.
 For detailed references see the literature on the relevant page of the website.
 Indicatively, on certain publications of scholars: Blake 1980, 93-112; Blake, Nepoti 1984, 354-368; Berti, Gelichi 1993, 125-199.
 Berti, Tongiorgi 1983, 37-79.
 Atti 1996.
 Hobart 2006.
 Berti 1996, 16, 23-26, fig. 1, fig. 3-9.
 In detail see Beliaev 2007, 133-140.
 For all relevant information: Hadjikyriakos 2006, 389-405.
 Indicatively, on relevant matters, see Megaw 1964-1965, 145-162; Nikolakopoulos 1978, 1-2; Berti 1992, 137; Castelletti 1994, 193; Berti 1996, 12-14; Tsouris 1998, 10-11.
 Nikolakopoulos 1978, 6-7; Tsouris 1996, 619; Yangaki 2010, 830; Yangaki 2013, 382.
 Yangaki 2010, 827-840.
 Gerola 1993, 254-255 note 479.
 See the relevant literature.
 For the first relevant information see Yangaki 2010, 827-840; Yangaki 2013, 375-384.
 Tsouris 1996, 603-624.
 For three indicative, relevant publications: Philon 1985, 299-320; Androudis 2007, 92-93· Androudis, Yangaki 2014, 51-60.