Take advantage of the search to browse through the World Heritage Centre information.

Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace

Date of Submission: 29/01/2018
Criteria: (ii)(iii)(iv)(vi)
Category: Cultural
Submitted by:
Ministry of Culture of Bulgaria
State, Province or Region:
Ref.: 6287

The Tentative Lists of States Parties are published by the World Heritage Centre at its website and/or in working documents in order to ensure transparency, access to information and to facilitate harmonization of Tentative Lists at regional and thematic levels.

The sole responsibility for the content of each Tentative List lies with the State Party concerned. The publication of the Tentative Lists does not imply the expression of any opinion whatsoever of the World Heritage Committee or of the World Heritage Centre or of the Secretariat of UNESCO concerning the legal status of any country, territory, city or area or of its boundaries.

Property names are listed in the language in which they have been submitted by the State Party


The serial property Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace is located on the territory of Plovdiv (Philippopolis in Antiquity). It consists of three immovable cultural monuments: Bishop's Basilica, Small Basilica and Late-Antique Irene Building, which were built and functioned during the 4th-6th centuries. The city is strategically situated at the crossroads of Europe and Asia Minor, in the middle of the Thracian lowlands, around seven unique hills. It is one of the oldest continuously inhabited cities in Europe, much older than ancient Troy.

Over the years, remains of ancient Philippopolis have been discovered during archaeological excavations. These include: fortified walls, a forum complex with an odeum in its northern end, a theatre, a stadium, an aqueduct, several early-Christian basilicas, etc. These monuments have been completely or partially preserved on site in order to be integrated into the modern city's environment. The floor mosaics from ancient Philippopolis, which have already been excavated and investigated, come from two basic periods: 2nd-3rd centuries and 4th-6th centuries. The first period mosaics belonged to thermae and representative buildings and have an air of western influence. By contrast, the early-Christian basilicas, residences and private homes of the second period bear the influence of eastern early-Christian centers. The mosaics have been preserved, investigated and published to different extents, depending on the possibilities of the time and the circumstances of their discovery.

Bishop's Basilica of Philippopolis

The Bishop's Basilica of Philippopolis was discovered during rescue archaeological excavations, carried out from 1982 to 1986. It is located to the east of the Forum Complex of ancient Philippopolis and to the south of modern-day St Ludwig Catholic Church. Until 2002 about half of the building was investigated and in 2016-2017 it was fully unearthed.

It is a three-nave basilica, with an apse to the east and a peculiarly shaped narthex and atrium to the west. Outstandingly large, it has lavish architectural interior and mosaic floors. It is about 83 m long and 36 m wide, which makes it the largest 4th-6th century basilica in Bulgaria and one of the largest on the Balkans.  

The basilica is accessible through five entrances on the west - three to the nave, one to the southern aisle and one to the northern aisle. The stylobates between the naves, made up of large marble quadrae, and several bases, capitals and column fragments are preserved in situ. The naves are separated by low brick walls, covered with stucco decoration and wall paintings. In the axis of the nave there is a massive marble ambo. Evidence of the altar structure is provided by a platform in the east end of the nave, which is surrounded by a marble altar screen, thus separating a presbytery. A distinctive feature of the liturgy planning is the presence of a peculiar deambulatory, through which the laymen could freely access the apse from the nave, going round the presbytery.    

The basilica was built over former monumental buildings and some of their structures have been archaeologically investigated. During construction, a wide street was specially built to the west of the atrium, leading to the late-Antique Irene building. The basilica functioned until the end of the 6th century and during the Middle Ages a Christian necropolis was built over its ruins. 

The floors of the three naves, the narthex and the atrium porticos are covered with mosaics with a total area of over 2000 sq.m. The stratigraphic research carried out during the conservation works identified three floors, laid on top of each other.  

The first floor was made up of pink mortar laid in opus signinum, with a terminus post quem determined by a coin of Emperor Licinius I (308-324) found in it. The second floor was made up of mosaic laid in opus tessellatum, in several stages between the mid-4th and early 5th centuries. The mosaic in the nave was laid first and the mosaic floors of both side aisles, the apse, the narthex, the porticos and the rooms in the southern portico were laid later. The third floor covers the earlier mosaics. It was laid in opus tessellatum between the late 5th and mid-6th centuries. 

According to composition and scale, iconography and decoration, materials and execution, the mosaics can be divided into three groups.

The earliest mosaic, laid only in the nave, differs significantly from the rest of the mosaics in the basilica. It is rather monochrome, large in scale, outstandingly monumental and bears the features of the early mosaics of Philippopolis, with a marked western influence. It is made up of one panel, which takes up the whole nave floor. The pattern consists of a network of intersecting octagons, forming a swastika meander and hexagons. The panel is framed by two spiral "running wave" borders and a composition of intersecting circles, forming quatrefoil rosettes. The mosaic-laying technique is opus tessellatum, with larger natural stone tesserae in four colours - white, grey-black, ochre and red.

The second floor mosaics, laid later in the side aisles, the apse and the porticos, are typical of the so called "purist style" that developed in the late 4th- early 5th centuries under the influence of the eastern early-Christian centres. They depict intricate polychrome geometric-ornamental compositions with extremely rich decoration, including numerous pre-Christian and early-Christian ornaments and symbols. The "purist style" was characterized by synthetic universality, balance between classical heritage and innovation, proportion and wealth of patterns and motifs, which made it popular even as late as the late-Byzantine period. In the centre of the southern aisle, a tabula ansata encircles a mosaic inscription with the name of the bishop [...]κιανοῦ, during whose time the mosaic was laid. The mosaic-laying technique is opus tessellatum, with smaller natural stone tesserae in eight colours, each with several different shades (white, ochre, pink, red, brown, blue, green and black). Some of the patterns were laid in the "rainbow style".

The third floor dates back to the second half of the 5th century and the early 6th century. The mosaics depict intricate geometric patterns, including figurative images of vases, flower baskets, plants and birds. The decoration and patterns were strongly influenced by the early-Christian centres in Asia Minor and Syria. The most impressive of them are: The Spring of Life scenes laid in the centre of each side aisle, the images of over 100 birds in the middle panel of the nave, as well as the rosette-like peacock with an opened tail, surrounded by other birds and two kantharoi, located  in the middle of the narthex. The mosaic-laying technique is opus tessellatum, with natural stone tesserae in seven colours, each with several different shades (white, ochre, red, brown, grey-blue, green and black).

The Bishop's Basilica of Philippopolis is unique in scale, architectural design and decoration and is one of the most representative early-Christian sites. It provides priceless information about the history of early Christianity and the formation and development of Christian art on the Balkans and in Europe. Its universal historical, archaeological, artistic, scientific and social value is undeniable.

Small Basilica of Philippopolis

The Small Basilica was discovered during rescue archaeological excavations, carried out in the centre of Plovdiv from 1988 to 1989. It is located on the eastern outskirts of the fortified city of Philippopolis, in close proximity to the fortification wall and to the east of the Bishop`s Basilica.

It is a three-nave basilica with an apse to the east, a chapel added to the south and floors decorated with polychrome mosaics. The building had two construction periods dated to the 5th-6th centuries, during which it kept its outer limits. During the second construction period the interior was renovated, the floor level was raised, a marble ambo was built, a synthron was constructed and a narthex was formed. A baptistery with a cross-shaped piscina and mosaic floor was added to the north-east end of the building.

The 5th century basilica floor is covered with polychrome mosaics laid in opus tesselatum, depicting mostly ornamental-geometric and floral images, such as guilloche swastika meanders and crosses, kantharos-vases, rosettes, Solomon knots, etc. In the nave, the tabula ansata in front of the altar screen has a donor's inscription. Based on epigraphic data, the inscription is dedicated to Basiliscus and his family. Flavius Basiliscus, the supreme commander of the Thracian army in the second half of the 5th century, had a residence in Philippopolis, and in 475 AD he became the Emperor of the Eastern Roman Empire.

The mosaic in the baptistery was laid in the 6th century onto an earlier brick floor. It depicts the exquisite polychrome figures of two stags and a couple of doves - traditional Christian symbols, which, together with the piscina, represent the Spring of Life scene. With its cross-shaped piscina and picturesque figurative images, the baptistery is so far the only monument of its kind in Bulgaria that has been conserved and displayed.

Produced by local workshops, the mosaics are similar to those form the Bishop`s Basilica, the Irene residential building and other sites from Philippopolis, and have high artistic, historical, scientific and exhibition value. 

Late-Antique Irene (EIPHNH) Building 

The late-Antique Irene building was discovered during rescue archaeological excavations, carried out in the centre of Plovdiv in 1983-1984. It is located in the centre of modern-day Plovdiv, to the north-east of the Forum Complex and to the north of the Bishop`s Basilica. The building, together with parts of the ancient street network, is preserved and displayed in situ in a modern-day pedestrian underpass named Archaeological.

The late-Antique residential building occupied two-thirds of an insula in the centre of ancient Philippopolis and had a representative part and domestic quarters. The representative part - a peristyle courtyard, surrounded by porticos and several rooms with polychrome mosaic floors, dates back to the 4th-6th centuries.

With a total area of 160 sq.m., the mosaics depict various geometric-ornamental compositions full of floral and figurative images. A series of greeting inscriptions guide the visitor from the entrance hall, through the portico, to the triclinium and the tablinum. The reception room floor is covered with a lavishly ornamented polychrome mosaic, whose focal point is a female image, a personification of the goddess Irene, bearing the inscription EIPHNH.

The polychrome mosaic floors were laid in opus tessellatum, with natural stone tesserae in different colours. The only exception is the Irene image, which was laid in opus vermiculatum, with smalt tesserae. The remains of a glass and smalt melting kiln, discovered in the peristyle courtyard, provide key evidence of the mosaic workshop practice. The mosaics date back to two basic periods of construction. The ones in the triclinium and the southern portico belong to the first period. The ones in the entrance hall, the eastern portico and the tablinum were laid later. The mosaics depict mostly geometric patterns, peculiar to late-Antiquity in the eastern Roman provinces. According to the paleographic investigation of the inscriptions, the earliest one, made around the second half of the 4th century, is the EIPHNH inscription on both sides of the female image. The greeting inscription at the entrance of the triclinium appeared about 30 years later, following a reconstruction of the mosaic floor. Together with it, an octahedral piscina was constructed, supplied with running water. The latest inscription, laid in the mid-to-late 5th century, is the one in the entrance hall. The name Desiderius mentioned in it can be interpreted as the name of the owner, and the contents of the inscription as a greeting.        

Evidence of the important place and role the owner of the Irene building played in the life of Philippopolis is provided by the cardo street that was specially built alongside the construction of the Bishop`s Basilica, as a direct connection between the two buildings.

Justification of Outstanding Universal Value

The serial property Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace is located on the territory of Plovdiv (Philippopolis in Antiquity). It consists of three immovable cultural monuments: Bishop`s Basilica, Small Basilica and Late-Antique Irene Building, which were built and functioned during the 4th-6th centuries.

Erected around the middle of the 4th century in the centre of the fortified city of Philippopolis, outstandingly large and lavishly decorated with mosaics and architectural elements, the Bishop`s Basilica is one of the earliest examples of Christian architecture on the Balkans and one of the few preserved monuments from that period. The distinctive features of its liturgy planning, particularly the possibility given to laymen to freely access the apse for veneration, were kept in all the later alterations of the basilica in the 5th and 6th centuries. The large-scale construction works, the extent of urban planning intervention and the high ecclesiastical and administrative status of the city provide evidence of the outstanding prosperity and social status of the local Christian community. During the construction of the Bishop`s Basilica, a new cardo street was built, leading from the basilica entrance to the late-Antique Irene building. Both buildings were functionally connected and their architectural decoration and mosaic floors are similar in character and time.

In the 5th century, the Bishop`s Basilica and the Irene building were renovated with mosaic floors, the same as the one laid in the newly-built Small Basilica. The several periods of existence of the two churches illustrate the development of liturgy planning in the province of Thrace and provide evidence of the liturgical dependence on Constantinople after the mid-5th century. During the last construction periods, ambos and synthrons were built in both churches, and a baptistery with a cross-shaped piscina crowned with a ciborium was added to the Small Basilica. At that time, mosaic floors were laid in the Bishop`s Basilica and in the Small Basilica baptistery.

The archaeological substance and the mosaics of all three properties are preserved and displayed in situ within the contemporary urban environment, thus presenting opportunities for further investigation. The mosaic floors from the 4th-6th centuries show that Christianity developed its own visual tradition, adopting symbols and scenes from pagan iconography, but giving them new meaning. They are representative of the stages of development of the church architecture and the late-Antique mosaic art of Thracian Philippopolis, as well as of the formation of an overall decoration system associated with the liturgical practices in the 4th-6th centuries. 

The proposal for inscription on the Tentative List of new cultural properties from the Republic of Bulgaria is based on a scientifically justified selection. The Bishop`s Basilica, the Small Basilica and the late-Antique Irene building belong to the same historical time period  - they were constructed and functioned in the 4th-6th centuries. Combining them in a serial property places focus on the heritage of early-Christian Philippopolis. The formation and development of a Christian community in the 4th century had a reflection on the city's planning, religious architecture and peculiar mosaic heritage.

Criterion (ii): During late-Antiquity, Philippopolis was one of the major cities of the Roman Empire and played an important role in human values exchange. Evidence of its multicultural environment, where many cults and religions coexisted and different influences were interwoven, is provided by the numerous unearthed buildings with mosaic floors - thermae, a synagogue, basilicas and rich dwellings. The late-Antique heritage of ancient Philippopolis, Roman Province of Thrace, sheds light on the formation and establishment of a peculiar mosaic workshop in Philippopolis, and also has an outstanding contribution to the investigation of the world's mosaic heritage.

Criterion (iii): The serial property Bishop`s Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace provides outstanding evidence of the cultural and construction traditions and the enormous late-Antique heritage of the Roman Empire. The monumental architecture of the early-Christian basilicas and the impressive mosaic floor heritage of late-Antique Philippopolis enrich our knowledge about the development and spread of construction practices and art throughout the empire.

Having adopted compositional schemes, decorative elements and building techniques from both the east and the west, the mosaics shed some new light on the establishment of a local mosaic workshop. In late Antiquity, it formed a specific, recognizable style of its own,  a combination of different influences and the local cultural tradition and resources.   

Criterion (iv): Several religious buildings from late-Antique Pilippopolis have been investigated - a synagogue, early-Christian basilicas, martyria and tombs, all of them lavishly decorated with mosaic floors and wall paintings. Two of them, the Bishop`s Basilica and the Small Basilica, have been preserved and displayed in situ; the mosaic floors of some of the remaining properties have been detached and displayed in museums.

The Bishop`s Basilica provides outstanding evidence of the development of early-Christian architecture. With a total area of 2000 sq.m., its floor mosaics are the largest preserved in situ mosaic floor of an early-Christian basilica from the 4th-6th centuries in Europe.    

Criterion (vi): The early appearance of Christianity in Thrace and the large Christian community of Philippopolis are evidenced by the revered by the Orthodox Church: St Hermes the Apostle, the first bishop of Philippopolis in the 1st century, St Theodota who died as a martyr in the 2nd century, during Emperor Hadrian's reign, and the 38 holy martyrs of Philippopolis, executed in the very beginning of the 4th century, during Diocletian's reign.

In the mid 4th century, the city already had a high social status and great prosperity, which resulted in the construction of the outstandingly large and lavishly decorated Bishop`s Basilica. Bishops from Philippopolis attended several church councils, and the bishopric hosted the members of the Arian party, who participated in the Council of Serdica in 343.

The Bishop`s Basilica provides valuable information about the development of liturgical practices until the end of the 6th century, but most of all, it sheds light on their formation and earliest stage.

Statements of authenticity and/or integrity

The authenticity of the archaeological sites included in the serial property Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace is high and undeniable.

Each of the three component parts had several construction periods and alterations in Late Antiquity, when they ceased to exist. The sites remained intact over the centuries until they were archaeologically investigated in the 1980s. Their archaeological substance has been preserved and displayed in situ.

The mosaic floors also have high authenticity. The mosaics are preserved and displayed in situ, after having undergone certain conservation interventions, determined by their condition and in accordance with the international standards and practices, based on respect for original material. Some of the mosaics in the Small Basilica  were detached from the site in the 1990s due to force majeure, but later they were returned to their original positions.

In 1995, each of the three sites was granted the status of a single cultural property of national significance. In 2017, Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace was granted the status of a serial property, and the boundaries and protection and management system were determined.

The serial property Bishop's Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace includes three outstandingly significant sites, which are functionally connected and provide new information about the earliest history of Christianity and the development of religious architecture and monumental art until the 7th century.

The unearthed archaeological substance in both basilicas completely clarifies their planning schemes, reflecting the liturgical practices in the 4th-6th centuries. Most of the late-Antique Irene building has been unearthed, thus providing enough information about its planning scheme, key location within the city and interconnectedness with the Bishop's Basilica.

The sites have been integrated in the contemporary urban environment, which has been specially transformed to provide conditions for proper display and protection from damage. In order to preserve the archaeological substance, protective buildings with adequate air conditioning have been constructed over the ruins of the Small Basilica and the Irene building. By 2019 a protective building is to be constructed over the ruins of the Bishop's Basilica.

Combining these three archaeological sites in a serial property contributes to the manifestation of their outstanding cultural value.

Comparison with other similar properties

The 4th century architectural plan of the Bishop`s Basilica is very similar in layout to the plans of the oldest known early-Christian basilicas from the time of Emperor Constantine the Great: Old St Peter's Basilica, San Paolo fuori le Mura in Rome and Church of the Nativity in Bethlehem. All of these were destroyed and new, larger cathedrals were built over them, currently inscribed on the World Heritage List. Information about the planning schemes and spatial structure of these early basilicas is provided by the reconstruction drawings that were made during different time periods.

Unlike these properties, the Bishop`s Basilica of Philippopolis has kept its original plan. It has an elongated plan, like the basilicas in Rome, and that distinguishes it from the ones in the Eastern Roman Empire. It differs significantly in the peculiar layout of its atrium and altar, with the presbytery located within the nave, thus forming a deambulatory in the apse.  

The closest to its plan, but belonging to a later time period, are: the basilica in Xanthos, inscribed on the World Heritage List as Xanthos-Letoon, and the basilica in Perinthos-Herakleia, but both of them have significant differences in the atrium and altar layout.

As to compositional schemes and decoration, the basilica's mosaic floors from the three construction periods have partial analogues.

Partial parallels of the composition and ornamentation of the earliest mosaic, laid in the nave in the middle of the 4th century, can be found in Bulgaria, but  they belong to sites with different purpose and function. These are: the floors of the Irene building in Plovdiv, the tomb in Diocletianopolis (Hissar), a city villa and a site in Stoletov Street from Augusta Trayana (Stara Zagora), Diophantus and Diogeneia residential building from Pautalia (Kyustendil), the Bishop`s Basilica in Sandanski. All of these belong to the mid to late 4th century, but they differ in the scale of composition and ornaments, the size of tesserae and partially in colours.

The mosaics that were laid later, between the mid-4th and early 5th centuries, are extremely intricate in composition, with a great variety of ornaments and impressive colours. An amazing fact is that their lavish colours are due solely to the rich palette of local natural stones that were mined from the nearby Rhodope Mountains. In this respect, they cannot be compared with any known mosaic. As to composition and ornamentation, they have partial parallels with mosaics from Antioch, Aquileia, Sardis, Syria, Israel, Jordan and Bulgaria. Bulgaria: second mosaic floor of the Synagogue in Plovdiv, basilica in the village of Gurmen, bath and peristyle building in Stara Zagora, basilica in Devnya, basilica in the village of Chomakovtsi, Kabille basilica, Filipovtsi Villa, etc.

The mosaics from the last floor of the basilica, laid between the late 5th and early 6th centuries, have partial parallels with the mosaics in the Xanthos basilica, inscribed on the World Heritage List as Xanthos-Letoon, and the basilica in Perinthos-Herakleia.

Some of the mosaics from the Small Basilica are closely analogous to the mosaics from the second construction period of the Irene building, the second mosaic floor of the synagogue in Plovdiv and the mosaic from the newly-discovered residence in Adana, Turkey.

The early mosaic floors of the Irene late-Antique building have partial parallels in Antioch and Zeugma, Turkey, and with elements of the early mosaic in the Bishop`s basilica of Philippopolis. The second period mosaics have analogues in the Small Basilica in Plovdiv, the basilica in Kabille, etc.

The mosaic floors from the serial property Bishop`s Basilica and Late-Antique Mosaics of Philippopolis, Roman Province of Thrace feature certain compositional schemes and decorative elements that were commonly used in the Roman Empire, but they have no explicit overall parallel with any known mosaic. They have a peculiar aspect of their own, a combination of different influences and local culture, traditions and resources, and enrich our knowledge of the development and spread of mosaic art in Late Antiquity.