Early Christian architecture

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The era of early Christian architecture begins with the sacred buildings erected in the 3rd century and ends with the end of antiquity , i.e. in the 7th century. Buildings from this period have largely survived in the Mediterranean area , but have often been renewed or significantly changed in the following architectural epochs.

Constantina Mausoleum, Rome around 337
Constantina Mausoleum, interior

Beginnings of early Christian church building

Church buildings were not required for the first two centuries AD. Because of the small size of the Christian congregations , there was no need for specially built worship rooms. In addition, the municipalities did not yet have a legal status that would have legally enabled them to purchase land or buildings. According to the written evidence that has been handed down, the services took place in the private homes of parishioners. (“(They) broke the bread in their houses and feasted together” Acts 2,46, similarly also Acts 20,7, Rom 16,5 and Col 4,15).

Another reason for the lack of church buildings in the first two centuries is to be found in the Christian image of God , which differed significantly from the ideas of other religions at the time. For the pagan inhabitants of Rome, the gods were personally present in the statues, which gave the temple such holiness that only the priests belonging to it were allowed to enter this sacred area; the service, which usually consisted of the presentation of offerings, therefore took place in the open in front of the temple .

The idea that the deity is permanently present in their meeting rooms was initially alien to the early Christians and consequently no fixed architectural form was required. One of the oldest surviving worship rooms, the house church of Dura Europos (around 232) on the Euphrates, shows that the early Christians took a more practical approach as soon as larger meeting rooms became necessary as a result of the growth of the congregations: They converted a building that had previously been used as a residential building, by removing walls and making additions; almost a hundred years later in Qirqbize (northern Syria) it happened the same way. The example of Dura Europos shows that even in this early period the rooms were decorated with Christian emblems and biblical representations on the walls.

  • Plan of the Christian house church of the 3rd century in Dura Europos

  • Ruins of the Christian house church of the 3rd century in Dura Europos

  • Reconstruction of the Baptistery, Yale University

  • Wall painting of the Good Shepherd, Dura Europos

  • Healing of the paralytic, Dura Europos

  • Jesus and Peter walk across the lake, Dura Europos

  • Samaritan woman at the well, Baptistery in Dura Europos

In the early Christian catacombs - especially in Rome - there were initially only sparse grave decorations, few inscriptions and no paintings in the 2nd and 3rd centuries; In the period that followed, the areas between the niche graves in the long underground passages and the walls and vaulted ceilings of the burial chambers were decorated with wall paintings.

The house churches that emerged at the beginning of the 3rd century were referred to as "house of God" ( domus Dei , Greek οίκος του Θεού) or "house of the community" ( domus ecclesiae = οίκος εκκλησίας) or "house of the Lord" ( dominicum = κυριακόν) or "House of God" (βασιλικός οίκος), from which the Latin expression basilica arose. In Rome, old house churches could not be archaeologically proven, neither under the foundation walls of the first title churches founded in the 4th and 5th centuries nor in other places in the city area, although the sources show that such meeting rooms already existed in private houses in the 3rd century to have. However, some Roman church buildings could be archaeologically proven that they go back to house churches; this is especially true of SS. Giovanni e Paolo. The archaeologists differentiate between private houses with Christian emblems or with a house chapel and the actual house churches, which represent a sacred meeting room ( ecclesia ). As early as the end of the 3rd century, the renovation of house churches or their foundations resulted in their own cult buildings as purely functional buildings, which are still of great importance in Christianity today as titular churches. Most of these early sacred buildings were destroyed around 303 during the period of persecution.

The house churches had gradually changed from mere meeting rooms to holy places. One of the witnesses of this change is the Greek writer Origen († 254), who recommended the parishioners to pray in the church, since this is where the power of the Lord is particularly palpable. From the 3rd century onwards, buildings were built especially for worship meetings. Clues can be found with Christian writers, but also in seizure protocols during the persecution of Christians. The early Christian writer Tertullian († after 220) wrote that the meeting places of Christians were “towering buildings”. The pagan philosopher Porphyrios († before 305) complains in his work “Against the Christians” that they built huge houses for their worship services, although they could pray in their own houses and God - according to Christian teaching - also answer these prayers there would. Emperor Diocletian († around 312) was so outraged by the size of a Christian church that he could see from the palace in his new royal seat Nicomedia that he had it destroyed as a prelude to his persecution of Christians. This first phase of early Christian church building ended with the persecution of Christians under Diocletian, during which worship spaces across the empire were destroyed or confiscated .

In a church ordinance created in Rome around 210 (ἀποστολικὴ παράδοσις = Traditio Apostolica ) no special architectural features for a Christian sacred building were specified; there was still no permanent place for the altar and no presbytery . Around 230, the Roman bishop Fabianus (236-250) began to set up an ecclesiastical territorial administration. He initially divided the city into seven districts, each with its own deacon , who was responsible for liturgical, catechetical and charitable tasks in his district and who was also responsible for the funeral system. Rome was official until the middle of the 4th century liturgical language the Greek ; the Latin language began to spread from the middle of the 3rd century.

Another church ordinance from the end of the 4th century (διδαχὴ τῶν ἀποστόλων = Apostolic Constitutions ) contains a special section on the "Duties of the clergy and the laity during worship" and on the "House of Assembly". This house should be an east-facing longitudinal building with lateral pastophoria , comparable to a ship, with a bishop's throne (καθέδρα) and priestly seats in the middle ( presbytery ) as well as standing room for the deacons, who "resemble the sailors" and those for separate seating arrangements for men To worry about women and children. “From a raised place in the center of the church” is read from the scriptures of the Old Testament and the New Testament . The doors are to be guarded "so that no unbeliever and no baptized person enter".

Church buildings after the Constantinian Revolution (313 AD)

After the recognition of Christianity (311) and the granting of complete freedom of religion (313), a large influx of Christian communities began. The goods of the church that had been confiscated during the previous persecution were returned so that the church buildings under Emperor Constantine the Great († 337) could be rebuilt or rebuilt larger and more splendid with state help.

The church foundations of Constantine and his family followed, especially in Rome, Ostia , Jerusalem , Bethlehem and Trier (as the temporary imperial residence of Augusta Treverorum ), but also in Byzantium , Asia Minor and Africa ; one speaks of a programmatic imperial building activity in the service of the Christian church. These cult buildings, which were supposed to visibly express the newly won self-confidence of Christians, were only noticeable from the outside because of their size; the outer walls consisted of brickwork ( opus latericium ) without decorative paving or cladding with hewn stones. On the other hand, they were decorated with imperial splendor inside. In this way, word worship and the Christian memorial meal were given the character of public state acts. The new framework gave the Christian celebration after the new liturgy at the same time imperial splendor and was also an expression of imperial power.

Basic architectural forms

In the course of the 4th century the basic architectural forms of Christian sacred buildings, which are still exemplary today, developed, favored by the trend-setting influence of the new religious policy of Emperor Constantine. In addition to the imperial court ceremonies and the ancient architectural forms in use up to now, important prerequisites were also the ideas and suggestions for the design of the Christian liturgy that the Roman bishops and their advisors sent to the builders. The planning master builders were initially the same who had previously been responsible for the imperial buildings.

The imperial palace in Spalato (Split), built by Emperor Diocletian near his Dalmatian birthplace between 295 and 305, is a good example of the architectural forms available at that time . In addition to the imperial representation rooms and the palace auditorium, four temples were built there, where the most important basic architectural forms for early Christian sacred buildings are already present, e.g. B. the simple rectangular temple with vestibule, the two pillared temple of Venus (hexagonal) and Cybele (round) as well as the mausoleum of Diocletian consecrated to Jupiter as an octagon with vestibule and colonnade within a rectangular courtyard, which was southeast of the decumanus . The palace auditorium with apse (apsid hall) and the “basement” hall below, in which three pillars on each side bear a cross barrel vault, a pre-form of the three-aisled basilica of Christian style, served as a model. Within the entire complex, the Cardo (north-south axis) and Decumanus (east-west axis) were lined with colonnades, which can be seen as preliminary forms for the atrium of an early Christian basilica.

  • Floor plan of Diocletian's Palace in Split

  • Reconstruction drawing of Diocletian's Palace in Split

  • Three-aisled cellar vault in Diocletian's Palace

  • Vestibule of Diocletian's Palace

  • Reconstruction of the Diocletian mausoleum

  • Reconstruction of the Diocletian mausoleum

  • Diocletian's mausoleum plan

  • Capital and decorative forms from the mausoleum

In the case of the new Christian sacred buildings, it was deliberately avoided to take up the construction of the Roman temples of gods, because they offered too little space and above all because the Christians of late antiquity did not want to adopt the types and forms of pagan cult buildings. In fact, there are only a handful of temples that have been converted into churches (such as the church of Santa Maria sopra Minerva in Assisi or the temple of Antoninus Pius and Faustina in Rome). Rather, the no longer needed and now vacant temples were used as "quarries": columns, capitals and wall cladding were broken out and put to new use in the churches.

Instead, they opted for the Roman basilica building type; because this was not designed for the pagan cult of gods and could be well adapted to local conditions. The Roman basilica was a secular cult building or palace that was used as a court, market or assembly hall. It consisted of a spacious hall divided by rows of columns, which was initially not designed as a directional building, but which was then increasingly oriented towards an architecturally accentuated apse, in which mostly a throne chair or a cult image stood. The new design of the Christian basilica was intended to be the "most successful type of sacred building in Western architectural history".

Floor plan of an early Christian basilica with a forecourt and cleaning well

The Christian basilica can be described as a longitudinal building with a raised central nave and two (or four) flanking side aisles , with pillars or columns with architrave beams or arcade arches supporting the upper aisle . The side aisles leaned with pent roofs against the wider and higher central nave, which was illuminated through windows in the upper aisle. The large windows in the central nave were mostly composed of several small, geometrically shaped panes of glass, but alabaster was also used; there were only small windows in the aisles. The central nave had a gable roof with either an open roof or a flat ceiling.

  • Plan of the Basilica of San Giovanni in Laterano

  • Plan of the Constantine Basilica of San Pietro in Vaticano

  • Drawing from 1693 of the Constantine Basilica of San Pietro in Vaticano

  • Model by Alt-St. Peter

The apse adjoining the central nave could have a semicircular or polygonal plan ; it formed the central part of the room for the clergy ( presbytery ) with the altar in the middle, in the curve surrounded by the priest's bench and the seat of the bishop (καθέδρα = cathedra). Opposite the apse there was usually an inner vestibule delimited by arcades ( narthex ) and the gable wall with one or more exits to the rectangular outer vestibule ( pronaos ). The catechumens who were not yet baptized and were not yet allowed to attend the Eucharist could stay here during the service . As a link to the outside world, the basilica was often preceded by an almost square forecourt ( atrium ). In the middle of it was a cleansing well called Cantharus . In the period that followed, there were additional rooms and facilities, including a transept , which can be seen in the floor plan as the shape of a Latin cross , a Schola cantorum with ambo and choir screens , galleries built in over the side aisles and ancillary rooms (pastophoria) for the preparation of church services.

The first Christian basilicas are the Basilica Salvatoris (315-318) founded by Constantine as Rome's episcopal church , today San Giovanni in Laterano ( Lateran basilica ), and San Pietro in Vaticano (317–322). This was followed by the six basilicas on the ancient consular streets outside the Aurelian city wall . This new type of building is a three-aisled pillar basilica, the side aisles of which run semicircularly around the central nave, while the central nave is kept open by pillar arcades for access in the aisles. A basilica was built either over a martyr's grave or in the immediate vicinity of martyrs' graves ; it served above all to keep the memory of the martyrs buried there alive through processions and parades in the surrounding aisles. In addition, the floor inside the church was covered with graves, which is why the basilica is also known as the Coemeterialbasilika or funeral basilica . This special form of early Christian church building only exists in Rome and there only within a period of 50 years from 315. The following structures are involved, of which - apart from San Sebastiano fuori le mura - only remains of rising masonry and foundations remain are:

Floor plans of the six basilicas on the same scale (from top left): Via Ardeatina, Basilica Apostolorum , SS. Marcellino e Pietro, Tor de'Schiavi, Sant'Agnese, Basilica maior

Other basilical church buildings that go back to Constantine are u. a .:

  • San Paolo fuori le mura : The Constantinian memorial basilica (around 324) was replaced by the so-called three emperors basilica (386–395) and rebuilt after the fire of 1823.
  • Church of the Nativity in Bethlehem: This church, consecrated before 335, was largely rebuilt in the second half of the 5th century after an earthquake.
  • Apostle Church (Constantinople) : This basilica, completed at the latest in 337, in the new capital founded by Constantine, was largely redesigned under Justinian I († 565) and demolished in 1461.

  • S. Paolo fuori le mura in Rome, plan of the basilica from 386

  • Nave of S. Paolo Fuori le Mura in Rome

  • Floor plan of the Church of the Nativity in Bethlehem

  • Illustration (985) of the destroyed Church of the Apostles in Constantinople

  • Floor plan of the Church of the Holy Sepulcher in Jerusalem, around 345

  • Reconstruction of the Church of the Holy Sepulcher in Jerusalem, around 345

The Christian central building also goes back to ancient roots . The late antique central buildings had a floor plan in the form of a circle, square, polygon or Greek cross. This design was used for Roman palaces ( Domus Aurea ), cult buildings ( Pantheon ), thermal baths ( Caracalla thermal baths ) or mausoleums ( Augustus mausoleum , Hadrian's mausoleum = Castel Sant'Angelo , Temple of Vesta (Forum Romanum) , tomb of Caecilia Metella ). One of the first Christian central buildings was the Church of the Holy Sepulcher in Jerusalem, begun in 326 and consecrated in 335 . In Rome, the best-known examples of Christian central buildings are the Lateran Baptistery , first built around 315 and rebuilt in 432 , the Helena mausoleum begun around 326 , the Constantina mausoleum built after 337 and the memorial and station church of Santo Stefano Rotondo, built from 462 .

  • Baptistery of San Giovanni in Fonte, Rome, around 315/432

  • Interior of the Lateran Baptistery, around 432

  • Helena Mausoleum, Rome around 326

  • Constantina Mausoleum, Rome after 337, etching by GB Piranesi, Rome 1756

  • Santo Stefano Rotondo, Rome around 462

Like the basilicas, the central buildings can be found in the entire Roman Empire and were also to be found north of the Alps. a. St. Gereon (Cologne). They were particularly widespread in the east of the empire and shaped architecture for centuries - starting from the Sergios and Bakchos Church in Constantinople (before 536) via San Vitale in Ravenna (before 547) to the octagon of the Aachen Cathedral (before 803).

The baptisteries were almost always built as a central building throughout the entire Reich. The countless surviving examples in Rome (Baptistery of San Giovanni in Fonte), Ravenna ( Baptistery of the Orthodox , Baptistery of the Arians ), Ephesus ( St. Mary's Church , St. John's Church) , but also in what was then Gaul ( Fréjus , Poitiers ) testify to the spread of this type of building.

  • Orthodox Baptistery in Ravenna, 5th century

  • Arian Baptistery in Ravenna, 5th century

  • Plan of St. Mary's Church in Ephesus, 4th to 6th century

  • Ruins of St. Mary's Church in Ephesus,

  • Plan of St. John's Church in Ephesus, around 550

  • Model of St. John's Church in Ephesus

  • Baptistery of the Cathedral of Fréjus, 5th century

  • Baptistery of St. Jean in Poitiers, 4th and 7th centuries

San Lorenzo Maggiore in Milan

The basic architectural forms of the Christian basilica and the central building occurred in any combination. The central buildings showed characteristics of the basilica churches: The example of the Basilica di San Lorenzo di Milano (from 372) shows that here too the atrium and narthex were in front of the actual church building. A century later, the Santo Stefano Rotondo church (consecrated before 483) was also built as a central building in Rome .

Equipment and image programs

The main distinguishing feature of early Christian churches is their interior fittings according to the standards of imperial representation. This is to be demonstrated by way of example in the first monumental Christian sacred building donated by Constantine, the Archibasilika Sanctissimi Salvatoris , today's Lateran basilica (315-318): The 19 pairs of columns in the central nave were made of rose granite , the 21 columns between the two side aisles were made of green marble ; they were spoils from ancient buildings that had been arranged in pairs when they were reused. The motif of the large mosaic in the apse calotte has not survived. The floor in the central nave was covered with yellow marble slabs; the side walls must be imagined with a covering of marble incrustations ( opus sectile ). The roof beams in the central nave are said to have been gilded. From the Liber Pontificalis it follows that Emperor Constantine for the Episcopal Church SS. Salvatore u. a. had donated seven silver altars, numerous silver candlesticks and a ciborium made of silver above the main altar. This precious furnishing “is regarded as materialized praise of God, but often also serves the glory of the builder and the founder”.

Apse mosaic (around 1200) based on an early Christian model in Alt-St. Peter, Rome

For the early Christian basilicas , single pictures and whole picture sequences were developed and executed as wall paintings or mosaics . According to Johannes G. Deckers, a three-part basic structure can be recognized:

- On the walls of the central nave, scenes from salvation history are depicted in a specific sequence; they are intended to remind of God's plan of salvation that was already realized in the past.

- The front walls of the apse arch mainly show scenes of homage to the Apocalypse ; the viewer should look ahead to the end of time and creation ( end times ), at which a triumphant Christ will return.

- In the apse an all-dominating image of God appears as a timeless divine majesty ( majestas Domini ).

In the early Christian central buildings , the images were usually arranged according to heavenly and earthly hierarchies :

- Above the wall plinth is the zone of the saints , to whom the believers can turn in case of need; In this zone, according to tradition, Emperor Constantine and Helena (mother Constantine the Great) are depicted, as well as other personalities and donors with their heavenly patrons.

- The next zone recalls the scenes of Christian salvation described in the New Testament: from the Incarnation to the death of Jesus and the Ascension of Christ .

- Prophets and angels are often depicted as heralds of the word of God.

- In the uppermost zone the creator and ruler of the universe appears, also as Christ in human form or symbolized by the cross .

The mosaics are among the particularly valuable early Christian furnishings . They were mainly attached to the apse and triumphal arch as well as to the nave walls in the large basilicas. The apse with the altar is the architecturally prominent and liturgically most important place in the basilica. That is why the highlight of the picture program is shown there: in the early days Christ as Pantocrator and World Judge in a paradisiacal landscape , partly surrounded by the Mother of God , the apostles and those saints who have a special relationship to the respective church. The theological statements about these images are conveyed through Christian symbols and symbols . In this way, the believing observer should be given an insight into the unearthly universe and into a heavenly world.

The special topic and the people, the symbols and symbols, but also the colors, orders of magnitude and numerical proportions used were created by artists - not known by name - according to a certain canon of images that was largely closed to fashion influences and the zeitgeist. Today, this canon can hardly be understood without explanation and it is also a puzzling question to the specialist.

The mosaics of the so-called classical period (4th to early 6th century) should appear precious and as if they were meant to last. They are or were to be found in: Lateran Basilica, Constantine Basilica of San Pietro in Vaticano, Mausoleum of Constantina, Santa Pudenziana , Santa Sabina , Santa Maria Maggiore , Imperial Basilica of Sancti Pauli extra muros, Santi Cosma e Damiano (Rome) .

Construction period after the fall of the Western Roman Empire (476 AD)

With the fall of the Roman Empire in the course of the Great Migration , a turning point was also made in architecture in the west of the former world empire. The Germanic conquerors did not have the artistic skills to construct comparable buildings. It was not until the later Romanesque period that churches were rebuilt on a larger scale. The buildings that have survived from this period show features of the architectural treasure trove of the Roman churches, which are uniform throughout the empire, but were also characterized by distinct regional peculiarities, from which independent styles developed. One of the best-known examples of this are the Visigoth buildings found in Spain and southern France .

Sant'Apollinare in Classe , apse mosaic around 549

Architecture in the Byzantine Empire

In the Eastern Empire, however, Roman lived on in Byzantine art and achieved a new, long-lasting bloom. After the reconquest of Italy by the Eastern Roman Emperor Justinian I in 476, this art returned to Italy, which numerous buildings, especially in Ravenna, bear testimony to today.

Web links

Commons : Early Christian Churches  - collection of pictures, videos and audio files
  • Church architecture in late antiquity and early Middle Ages: pagan basilica, Christian basilica, central building, baptistery (PDF; 745 kB)

literature

  • Mariano Armellini: Le Chiese di Roma dal secolo IV al XIX , Vol. 1-2, Rome 1942.
  • Xavier Barral i Altet: Early Middle Ages. From late antiquity to the year 1000 . Taschen, Cologne 1999.
  • Martin Biddle among others: The Holy Sepulcher in Jerusalem . Belser, Stuttgart 2000.
  • Hugo Brandenburg: The early Christian churches in Rome from the 4th to the 7th century . Schnell & Steiner, Regensburg 2013.
  • Walther Buchowiecki: Handbook of the Churches of Rome. The Roman sacred building in history and art from early Christian times to the present . Hollinek, Vienna 1967–1997, Vol. 1–4.
  • Peter C. Claussen and Darko Senekovic: S. Giovanni in Laterano . With a contribution by Darko Senekovic about S. Giovanni in Fonte (= Corpus cosmatorum. Volume II, 2). Franz Steiner, Stuttgart 2008.
  • Johannes G. Deckers: The early Christian and Byzantine art . 2nd edition, Munich 2016.
  • Arne Effenberger: Early Christian Art and Culture. From the beginning to the 7th century . Koehler and Amelang, Munich 1986.
  • August Heisenberg: Church of the Holy Sepulcher and Church of the Apostles. Two basilicas of Constantine . Second part: The Apostle Church in Constantinople. Hinrich, Leipzig 1908.
  • Ulrich Mell: Christian house church and New Testament. The iconology of the Baptistery by Dura Europos and the Diatessaron Tatian (= Novum Testamentum et Orbis Antiquus. Volume 77). Vandenhoeck & Ruprecht, Göttingen 2010.
  • Herbert Alexander Stützer: Early Christian Art in Rome . Ostfildern 1991.
  • Matthias Untermann: Architecture in the Early Middle Ages , wbg Academic, Darmstadt 2006
  • Hans Georg Wehrens: Rome - The Christian sacred buildings from the 4th to the 9th century - A Vademecum . Herder, 2nd edition, Freiburg 2017.

Individual evidence

  1. ↑ " Breaking bread " is the name common in the early days of the church for the Sunday gatherings of the young community based on the last supper of Jesus , which he celebrated with his apostles on the eve of his execution and which is regarded in the church as the first Holy Mass
  2. ^ Hugo Brandenburg: The early Christian churches in Rome from the 4th to the 7th century, Regensburg 2013, p. 11
  3. ^ Arne Effenberger: Early Christian art and culture. From the beginnings to the 7th century, Munich 1986, pp. 87ff.
  4. ^ Hugo Brandenburg: The early Christian churches in Rome from the 4th to the 7th century, Regensburg 2013, p. 11ff.
  5. ↑ Origen: De Oratione 31.5
  6. ^ Tertullian: Adversus Valentinum 2,3
  7. ↑ Porphyrios: Adversus Christianos, fragment 76
  8. ↑ Hugo Brandenburg: The early Christian churches in Rome from the 4th to the 7th century, Regensburg 2013, p. 13
  9. ↑ Lexicon for Theology and Church (LThK), Freiburg 2006, Volume 3, Sp. 1146f.
  10. ↑ Ferdinand Boxler: The so-called Apostolic Constitutions and Canons, Kempten 1874, 2nd book, chapter 57
  11. ↑ Johannes G. Deckers: The early Christian and Byzantine art. Munich, 2nd edition 2016, p. 57ff.
  12. ↑ Hans Georg Wehrens: Rome - The Christian Sacred Buildings from the 4th to the 9th Century - A Vademecum, Freiburg, 2nd edition 2017, p. 31f.
  13. ^ Andreas Tönnesmann: Kleine Kunstgeschichte Roms, Munich 2002, p. 19ff. (23)
  14. ^ Arne Effenberger: Early Christian art and culture. From the beginnings to the 7th century, Munich 1986, p. 104ff.
  15. ↑ Hans Georg Wehrens: Rome - The Christian Sacred Buildings from the 4th to the 9th Century - Ein Vademecum, Freiburg, 2nd edition 2017, pp. 67-104
  16. ↑ Johannes G. Deckers: The early Christian and Byzantine art. Munich, 2nd edition 2016, pp. 69ff.
  17. ↑ Johannes G. Deckers: The early Christian and Byzantine art, Munich, 2nd edition 2016, p. 60.
  18. ↑ Johannes G. Deckers: The early Christian and Byzantine art, Munich, 2nd edition 2016, p. 64
  19. ↑ Johannes G. Deckers: The early Christian and Byzantine art, Munich, 2nd edition 2016, p. 77ff.
  20. ↑ Joachim Poeschke: Mosaics in Italy 300-1300, Munich 2009, 9ff.
  21. ↑ Hans Georg Wehrens: Rome - The Christian Sacred Buildings from the 4th to the 9th Century - Ein Vademecum, Freiburg, 2nd edition 2017, p. 40ff.