Workshop for Conservation of Roman Mosaics 2024 (Balkan Heritage Field School)

Archaeological Context & Period

Why Stobi? The first historic records to mention Stobi are by the Roman historian Titus Livy (ca. 197 BCE). According to Livy, Stobi became an important center for salt trading after the Roman conquests of Macedonia and the establishment of Pax Romana. In 69 CE, Emperor Vespasian granted Stobi the rank of municipium and the right to mint its own coins. Stobi was not only an important salt trading center but also strategically located at the crossroads of the ancient roads that ran along the two rivers Axios and Erigon. The first road connected the North and the South of the Balkans as it does today, while the second to the southwest connected Stobi with Via Egnatia near Heraclea Lyncestis and to the northeast it continued to Serdica.

This commercial and strategic position brought Stobi long-term prosperity, especially in the period between the 1 ^st and 3^rd centuries CE. Several monumental buildings in the city are dated to this period: the Theatre, the first City Wall, Porta Heraclea, Public Building with Arches (most likely the Stobi library), Casa Romana, the Synagogue, as well as the water supply system. In 267 CE the city suffered Goths and Herules raids. At the end of the 3rd century Stobi was devastated by an earthquake, later rebuilt, but following a different urban plan. Most of the ruins visible today belong to buildings dated to this period.

In the 4 ^th century CE, Stobi became an important Christian center and the seat of powerful bishops. In the 5^th– 6^th centuries, Stobi was the capital city of the Roman province Macedonia Secunda, but suffered from the raids of Huns, Ostrogoths, Avars and Slavs. The constant threat of barbarian raids, as well as certain climatic changes lead to the gradual abandonment of the city in the second half of the 6^th century CE. Some records mention a small Slav community that settled and lived there in later centuries. The last historical reference regarding Stobi describes the victory of the Byzantine troops over Stobi’s local militia during the 11^th century CE.

Approximately 1560 square meters of the excavated territory of the ancient city of Stobi are covered either entirely or partly in preserved mosaics, dated mostly between the 2nd and 6th century CE. Most of them were discovered in the public or residential Roman and Late Roman buildings at the site: the Episcopal Basilica, the Extramural Basilica, the Theodosian Palace, the Synagogue II, the “Casino”, the House of Peristeria and the House of Polycharmos. Variations of geometric, floral and animal motifs are represented in the most popular ancient mosaic techniques: opus tesselatum, opus sectile as well as opus barbaricum and opus vermiculatum.

n 2018-2019 the conservation activities during the workshop were focused on the mosaic floor in Room 1 of the House of Parthenius. The first conservation treatment of this mosaic was performed in the 1930’s and until 2018, the mosaic was covered with sand, and never properly documented. The condition of this mosaic was extremely bad: layer detachments, degraded nucleus, bulges, depressions, cracks, lacunae, missing and detached tesserae all over the surface, dirt layer deposits, incrustations, different problems caused by vegetation and insects, deteriorated infill’s of lacunae and edge repairs etc., thus giving the opportunity to the participants to see and solve almost every kind of problem that can occur during mosaic in situ conservation. Participants took part in mechanical cleaning of the mosaic surface, removing the old and deteriorated cement repairs, stabilizing and consolidating the mosaic structure, injecting of liquid mortar, replacing destroyed nucleus, filling the lacunae, edge repairs, and resetting tesserae. All the processes were followed up with new technical and photo documentation using the advanced technique of photogrammetry.

After two seasons of in situ conservation of this mosaic, together with the participants, we have stabilized almost the entire surface of the mosaic with all the above-mentioned techniques. It is necessary to continue the good practices until this project is completed and the mosaic is on display to the public. Consequently, this mosaic will be again in the focus of the workshop in 2023.

In additional to all the mosaics that have been documented, conserved, restored and displayed in the Archaeological site of Stobi, the most important outcome of this project is the students who have participated in the workshops and gained experience and both theoretical and practical knowledge in valuation and preservation of cultural heritage.