The Basilica “St. Sophia”
The “St. Sophia” basilica, after which modern Sofia is named, was built over the remains of several early Christian churches. The earliest church dates to the beginning of the 4th century and the latest from the second half of Emperor Justinian I’s reign (527-565). Today the mosaics from the earliest church are preserved in situ, but fragments from later mosaics floors as well as single tesserae from wall mosaics have also been discovered and conserved.
The first church was a small cemetery church (see Church I on the plan) and possibly a martyrium. Its mosaics are important evidence for the history of Christianity’s hidden presence in Serdica before 311-313 and the early days of Christianity’s public presence in the city from emperor Constantine I’s reign until the end of the 6th century. Although no historical sources mention martyrs at Serdica, during the Tetrarchy and especially the reign of emperors Diocletian (284-305) and Galerius (305-311) a large-scale persecution of Christians was authorized across the Roman Empire, including in the Balkans. Galerius’ frequent and prolonged trips to Serdica would have dissuaded Serdica’s Christians from gathering and paying respects to any martyrs. The situation changed drastically in 311, however, when shortly before his death emperor Galerius issued the first edict for religious tolerance, which allowed Christianity to become an officially recognized religion in the Roman Empire.
This edict marked a turning point for Serdica’s Christians since for the first time they could openly express their religious beliefs and pay respects to two now unknown martyrs. Two silver reliquaries found in a small “grave” beneath the altar table of the earliest St. Sophia church/martyrium seem to have honored these martyrs. A third reliquary was discovered in a tomb in the eastern necropolis of Serdica that was built after the martyrium. The two silver reliquaries, a high concentration of graves around the earliest buildings surrounding “St. Sophia”, and the mosaic scene in the apse of the martyrium testify to the active faith of Serdica’s Christians in the early days of Christianity’s public presence in the city.
Between the second quarter and middle of the 4th century, Christian communities were generally of humble financial means and so could not afford to build churches with expensive decorations. This is why Serdica’s first church/ martyrium had a single interior space and was decorated with the cheapest mosaic technique, opus signinum.
This is the mosaic from the apse depicting two cypress trees—a popular motif in funerary art and the decoration of martyria—with massive vines twisted around them. They are very schematic in execution, which contrasts with their rich, predominantly red and green color palette. The style of the trees resembles that of the massive vines on the sarcophagus of Emperor Constantine’s mother Helena and on some wall mosaics in “Santa Constanza,” both at Rome. At the mosaic’s center is a vase with a palm branch and two birds pecking at it. This scene originates in the Hellenistic period (the 3rd – 1st century BCE) when the famous mosaic artist Sosus of Pergamon created its original version of doves perched on a vessel and drinking water from it. The painstaking detail of the doves’ coloring and of their reflections in the water create the illusion that the birds are real.
Since this original, the iconography of birds perched on a vessel became so popular that it was reproduced in many varieties not just in Antiquity but in the Middle Ages as well (Popova 2017b). In the case of Serdica’s first church/martyrium, the motif was reimagined to carry a Christian message. The palm branch is specifically chosen as a Christian symbol of victory over death, of the martyr’s sacrifice, and Jesus Christ’s atonement for original sin, thereby giving Christians the gift of eternal bliss in the kingdom of heaven. The birds pecking at the branch and flowers symbolize this spiritual fulfillment. Thus, all the mosaic’s decorative elements emphasize the promise of heaven for the martyr and all righteous Christian faithful. This mosaic was the work of an unknown workshop and is later than the earliest western part of the basilica, but it predates the mosaic from the chancel. It probably dates to the period from the end of Constantius II’s reign in 361 until the Valentinian dynasty (363-379), excepting the reign of Emperor Julian the Apostate (361-363) when Christianity was out-of-favor with imperial authority.
The cult towards Christian martyrs and their relics
During this early stage of Christianity as a legally permissible religion in the Empire, there were no official canonical or state regulations governing how to preserve and worship the relics of martyrs. Still, such remains were highly sought after for burial in or beneath the altar, crypt, columns, etc. in order to “fortify” the practice of worshipers’ faith. Later, such relics became essential for the consecration of every church. According to liturgical canon, a church could not be consecrated without them.. It is unknown when this church law was enacted, and it likely did not go into effect simultaneously across all Roman provinces since early Christianity was administratively decentralized. The first centers for the early Christian Church with their own liturgy, language and rituals formed toward the late 4th and early 5th century.
Since the mid-5th century, martyr’s relics were intentionally split into multiple pieces to satisfy demand for them. Relics were placed in encolpia (crosses that clergy wore around their necks), and in reliquaries made from clay, stone (most often marble), bone, or silver or gold and decorated with reliefs or precious stones. At first, reliquaries were buried around a martyr’s grave or a church’s altar, but from the second half of the 4th century a special kind of crypt emerged. These crypts had windows called fenestella that allowed worshippers to see and touch the relics to receive a blessing from them.
The conversion of Serdica’s first church/martyrium into a cemetery church (see church II on the plan) and the appearance of mosaics in the more expensive opus tessellatum technique show that the Christian Church at Serdica had gradually become more affluent. This was in part a product of a new imperial policy of annual state subsidies and legally encouraged private donations to the Church. Moreover, Emperor Constantine I and his family set an example for all other elites with their exceedingly generous personal donations of land, money, silver, and gold for the construction and decoration of Christian churches in Rome, Jerusalem, and quite likely his self-professed favorite city Serdica.
The earliest mosaic made in opus tessellatum is located in the western part of the “St. Sophia” basilica, which had the same floor plan as the earlier church (church I) but extended further to the west. In its motifs and colors, this mosaic closely resembles the one discovered in the “House of Felix,” a 4th century domus at Serdica. The mosaic’s geometric decorations also contain crescents, floral elements, palmettoes, and in a few places kantharoi (wide-brimmed wine-mixing vessels) with birds. The mosaic dates between the second quarter and middle of the 4th century based on its style, its resemblance to the mosaic in the “House of Felix”, and coins discovered around it.
Church II was decorated with three mosaic compositions in three different styles, but the mosaics were not placed all at once but rather over time as the church acquired necessary funds and was renovated according to liturgical changes. The latest-dating mosaic of the three, which is set in the chancel, consists of separate panels that depict major Christian symbols such as a kantharos containing Communion wine and bearing peacocks, symbols of eternal life in heaven. The most important central panel depicts two lambs, probably with a cross between them (the cross depiction is not preserved). Such iconography is typical for mosaics in early Christian martyria. Not all of the panels in the chancel are high-quality; some are very schematic, composed of large tesserae, and asymmetrical. These panels are not original but were installed later than the altar. This is apparent in these panels’ irregular plan, their awkward placement around the altar, and the style of the many figures they depict, which are more typical of the late 4th – beginning of the 5th century or the reigns of Emperor Theodosius I (379-395) and his heirs.
Mosaic from the three-aisled basilica beneath “St. Sophia”
The mosaic is laid 30 cm above the “lower one” and probably belongs to the penultimate basilica at the site of St. Sophia (see church III on the plan). This second basilica was built partially on top of the earlier church II but had three aisles and a “Syrian type” apse. The mosaic from the basilica, which consists of five panels, was set in its nave and was found preserved up to the chancel (Pillinger et al. 2016, No 66, 300 – 317).
The mosaic’s central panel has a rectangular shape with an inscribed square and circle, the latter of which contains the symbolic “spring of life” scene or a kantharos (a wide-brimmed vase) containing wine for Communion. The corners of the square also hold four kantharoi sprouting vines. The square field itself is flanked by intersecting circles that form four-leaf rosette shapes.
The rest of the mosaic’s panels are: octagonal and separated by squares, square and holding four triangles that form a star; and square holding bent at an angle and straight standing figures with straight and inclined figures with eight-pointed stars between them. Most octagons contain rosettes, “Solomon knots,” crosses, palm branches, and geometric figures. Two of the panels oriented north-south are framed by alternating rectangles and squares with inscribed rhomboids and circles holding rosettes or a large heart-shaped leaf.
A long narrow border and second wider frame oriented east-west separate the five mosaic panels in the nave from three other mosaics with ornamental geometric decoration. These three panels probably belong to the basilica’s northern aisle even though their compositions are similar to those in the nave, except that they include more floral elements, shields and cubic shapes. Based on coins discovered between the “upper” and “lower” mosaic, the “upper” one was created during or after the reign of Emperor Arcadius (395-408).
Wall mosaics in Justinian’s “St. Sophia”
The magnificent “St. Sophia” church in Serdica was erected during the second half of Emperor Justinian’s reign. Single tesserae made of colored glass and covered in gold leaf were discovered during excavations at the end of the 19th and beginning of the 20th centuries. Based on these finds, archaeologists believe that the walls and domes of the last and most impressive of the four churches “St. Sophia” were decorated with mosaics. These type of tesserae are typical for the opus musivum technique, which is too fragile for floor decoration. Further support for this theory is the fact that besides borrowing the name “St. Sophia” from the original in Constantinople, almost all basilicas constructed in Justinian’s time not only in the capital but also in the Balkans and Asia Minor followed the same decorative scheme. Unfortunately, the wall mosaics from Serdica’s “St. Sophia” do not survive because this church’s original walls and arches were destroyed by multiple earthquakes, invasions, and fires and then rebuilt less extravagantly several times.