One of the key issues in studying
Late Antiquity is the continuity of urban life. Significant attention is devoted to examining the transformation of the ancient city into the
medieval city. Since the second half of the 20th century, extensive archaeological research has been conducted in this area. A valuable complement to these studies is the comparison of archaeological data with written sources, and in this regard,
Procopius' treatise
On Buildings is a crucial and unique source.
On Buildings is a repository of invaluable information about construction activities in the
Mediterranean region during the 6th century. Some cities mentioned in the treatise are known only from this text. No other document of this kind has survived. Although the work's importance as a source for
archaeological studies has always been recognized, and as early as 1972, James Evans called
On Buildings a source "providing a full and remarkably accurate account of Justinian's building program," only recently has it undergone critical scrutiny. Modern researchers have identified numerous inaccuracies, particularly in attributing construction projects to
Justinian I that were actually carried out under
Justin I or even
Anastasius I. Additionally, there are unexplained and surprising omissions.
Structure of the Work The treatise, consisting of six books, begins with a
rhetorical introduction, a
captatio benevolentiae. The author first emphasizes the importance of historical science, then praises Emperor
Justinian I, ranking him above ancient rulers
Themistocles and
Cyrus II; Procopius also portrays the emperor as a conqueror and legislator. The substantive content starts with a description of the empire's capital,
Constantinople, with Book I primarily devoted to its ecclesiastical buildings. Book II covers fortifications in
Mesopotamia, while Book III addresses those in
Armenia. Book IV lists fortresses and other military structures on the
Balkan Peninsula. In Book V, the author discusses constructed and restored buildings in
Asia Minor and
Palestine. Book VI is dedicated to
Egypt,
Cyrenaica,
Tripolitania, and other provinces of
Byzantine Africa. The narrative in each book revolves around the main cities of the respective region: Constantinople (I),
Dara (II),
Martyrdom and
Theodosiopolis (III),
Justiniana Prima (IV),
Jerusalem (V), and
Leptis Magna (VI). This organizational structure aligns with the traditional scheme used by ancient geographers — such as
Hecataeus,
Pseudo-Scylax,
Strabo, and others—progressing from east to west and north to south. According to Glannville Downey's 1947 opinion, the work, as it has come down to us, is incomplete. This is evidenced by the absence of any discussion of buildings in
Italy, despite Procopius mentioning its conquest. Downey suggests that the composition of the later books further indicates incompleteness: Procopius' promise at the start of Book V to discuss "the rest of Asia and Libya" is fulfilled only in Book VI. Downey concludes that Book VI was originally part of Book V, supported by the brevity of these books, which together match the length of Books I, II, and IV. Additionally, unlike the other books, Book VI lacks references to the preceding book and does not begin with a brief note on the region's significance. The degree of the work's completion can also be assessed by analyzing its editorial thoroughness. Downey examined three lengthy lists of buildings (in sections IV.IV, IV.XI, and V.IX). He suggests the first two were based on government archives to which Procopius had access, while the third may have relied on an official source or the author's personal notes. The first list is more carefully crafted, clearly distinguishing between newly built and restored fortifications. The second list lacks this distinction, possibly reflecting differences in source quality. However, one would expect the author to eliminate duplicates and barbarisms during editing, standardizing fortress names to match official Greek documents. Yet, the second list contains three geographical names likely referring to the same place. The third list, dedicated to
Phoenicia, includes entries related to
Syria, indicating a lack of thorough editing. The near-identical repetition of text about the walls of Chalcis may be a scribal error, as suggested by text editor
Jacob Haury, or refer to two distinct cities with similar names (
Chalcis ad Belum in Syria and Chalcis in
Lebanon, near modern
Majdal Anjar), or it may reflect incomplete editorial work, with Procopius undecided on the placement of the Chalcis walls reference. The second option is less likely, as the Lebanese Chalcis had been obscure for centuries, while a 550 inscription confirms the rebuilding of the Syrian Chalcis' walls. In 1985,
Averil Cameron concurred with the view that the work is incomplete. She notes not only the absence of information about Italy but also a qualitative shift in Books IV and V, which consist largely of lists. She rejects the hypothesis of German historian Berthold Rubin (1954), who argued that the omission of Italy was due to its limited contribution to the glory of
Belisarius — Cameron argues the work was addressed directly to the emperor and aimed to glorify
Justinian I's achievements.
Book I: Constantinople Book I of
On Buildings focuses primarily on the ecclesiastical constructions of
Constantinople. Historians consider it the most literarily polished. In it,
Justinian I is presented as the model Christian ruler, adorning his capital with magnificent structures. In this context, the book is a primary focus for studying whether the work as a whole is a
panegyric. Modern scholars examine the text of Book I from various perspectives. The significance of the history of the
Hagia Sophia for dating the work is discussed above. The use of certain words by Procopius and the nuances of their meanings have also been studied, with researchers seeking evidence of hidden irony or indications of Procopius' true attitude toward the emperor. Several artistic images used by Procopius in this book have drawn scholarly attention. For instance, describing the famous equestrian statue of the emperor atop the
Column of Justinian, Procopius writes that it is "clad in armor, as in heroic times; his head is covered with a helmet that seems to move: such a radiance, as if lightning, emanates from him. If one were to speak in poetic terms, it shines like an autumn star." Given the earlier mention of
Achilles and the fact that, for a classically educated 6th-century reader, a poetic allusion typically referred to
Homer, this likely points to a passage in the
Iliad where the hero is compared to a star "that rises in autumn with fiery rays." However, that star is an ominous portent, "bringing evil pestilence to wretched mortals". In the same book, Procopius compares Justinian to two notable ancient rulers,
Themistocles and
Cyrus the Great. According to
Plutarch, Themistocles was of obscure and barbarian origin, while Cyrus led
Persia, a state historically hostile to classical civilization. These themes—Justinian's questionable origins and hostility to the
Roman state—are central to the Secret History. Thus, according to Anthony Kaldellis,
On Buildings reveals a subtle opposition in the author's stance.
Book II: Mesopotamia in 1911. A significant portion of Book II of
On Buildings is devoted to Justinian's efforts in developing the fortress of
Dara. Built on the site of a small village after the unsuccessful
Persian war of 502–506, Dara served as a base for future operations against the
Sasanian Empire. With reliable water sources and a strategic location, the fortress had advantages over the older
Amida. Initial fortifications were constructed in 505–507 under Emperor
Anastasius I, who named the city after himself and made it the residence of the
dux of
Mesopotamia. Subsequent events confirmed the site's suitability and the fortifications' reliability. Dara withstood a siege during the first of
Justinian's wars with Persia, followed by
Belisarius's
victory over the Persians in 530. During the next war (539–544), when
Antioch fell in 540, only Dara resisted a Persian siege. The fortress was renovated under Justinian but fell in 573. Due to its significance, Dara's history is documented in numerous sources, including eyewitness accounts in Procopius'
History of the Wars, as well as works by
Joshua the Stylite,
Zacharias Rhetor,
John Malalas, and others. In
On Buildings, Procopius' account of Dara is highly detailed, second only to his description of
Constantinople. It likely serves as a model for describing Justinian's achievements in securing the empire. The narrative structure is typical of the work: a brief history of the fortress's establishment, followed by descriptions of its fortifications, water supply, public buildings, and churches. Verification of Procopius' claims about Dara has been conducted through comparisons with other sources and archaeological data. His assertions that Justinian built barracks and two churches ("the great church" and one dedicated to
Bartholomew the Apostle) are questionable, as it is surprising that barracks were not built earlier given the fortress's military importance, and other sources indicate the churches were constructed under Anastasius. Procopius' account of the fortress's walls is also dubious. He claims the walls inherited by Justinian were too low and insufficient for defense, with many towers heavily damaged, contradicting
Joshua the Stylite's testimony that the fortress withstood a Persian siege soon after its construction. Moreover, in his own account of the 530 events in the
History of the Wars, Procopius gives no indication that Dara's walls were unreliable. He describes Justinian's improvements to the walls as follows: "Above them, he built a wall thirty feet high along the entire circuit; in thickness, he did not make it full size, fearing that excessive weight would irreparably harm the structure if the foundation were overburdened: he surrounded this level with a stone structure, built a gallery around the entire wall, and above the gallery erected battlements, so the wall had two levels throughout, and in the towers, there were even three places from which defenders repelled attackers." Procopius did not revisit these areas, and his account of the 540 siege in the
Persian War relies on secondhand information, stating that "the city was surrounded by two walls, the inner one being of great size and truly remarkable (each tower rose to a hundred feet, and the rest of the wall was sixty feet high; the outer wall was much smaller but still strong and impressive)." Thus, these improvements were made in the 530s. Since the
Arab conquest, the fortress fell into ruin, with only a small village remaining, rarely visited by European researchers. The fortifications gradually deteriorated and are now in worse condition than when photographed by English traveler
Gertrude Bell in 1911. In 1983, Brian Croke and James Crow analyzed the ruins' condition based on field research, identifying remains of several towers and
water gates with two types of masonry: Type A, made of higher-quality stone, and Type B, likely from repair work. They proposed two phases of fortification construction, attributed to the reigns of
Anastasius I and
Justinian I, respectively, in the absence of additional archaeological or
epigraphic evidence. While the poor state of the fortifications makes some of Procopius' claims unverifiable, researchers identified instances of inaccurate descriptions, exaggeration of Justinian's achievements, and omission of Anastasius' contributions, such as the massive "Hercules Tower," which dominated the fortress even in 573. Historians also analyzed Procopius' claims about Dara's water supply improvements, linked to the discovery of an
underground river that suddenly appeared and damaged parts of the wall. Written evidence suggests this river was known in Dara during Anastasius' reign, and observations do not support Procopius' account.
Book III: Armenia and Crimea In Book III, describing Justinian's achievements in
Crimea, Procopius mentions four locations (
Chersonesus, Bosporus,
Alusta, and Gorzubitae) and a
Gothic region called Dory. Scholars of early medieval Crimea have repeatedly addressed the localization of Dory, attempting to pinpoint its location based on Procopius' brief references. Various theories exist, but the prevailing view places Dory in southwestern Crimea, in the
Crimean highlands, around
Mangup and its environs, covering a significant area. Later, this region became the
Principality of Theodoro and, ecclesiastically, the Gothic Diocese. The mention of the so-called "long walls" is crucial for determining the Gothic territory: "Since their region seemed easily accessible to enemy attacks, the emperor fortified all entry points with long walls, thus relieving the Goths of fear of invasion". Research conducted in the 1950s by the Institute of Archaeology of the
National Academy of Sciences of Ukraine was not completed, leaving the issue unresolved. The question of whom these walls protected the Goths from remains unanswered, possibly descendants of the
Tauri, pushed to the northern peninsula. Opinions vary on the reliability of this information. Procopius likely deserves trust only in the sense that his reports lack fabricated details or deliberate falsifications. However, due to his limited knowledge, his information is imprecise. He likely had poor familiarity with the northern and eastern
Black Sea coasts, and his description of Dory's customs resembles a passage from
Tacitus'
Germania.
Book IV: Balkans and Greece . However, they are not mentioned by Procopius and may have been built in earlier reigns. In Book IV, dedicated to
Justinian I's activities in the
Balkans, Procopius lists over 600 locations where fortifications were built or restored, though only a small portion has been reliably identified. According to
Edward Gibbon, "they mostly consisted of stone or brick towers rising within a square or circular area, surrounded by a wall or moat, serving as refuges for peasants and livestock from nearby villages during emergencies". Gibbon's assessment is considered broadly accurate due to limited archaeological evidence. Excavations by Bulgarian archaeologists, starting with Ivan Velkov in the 1930s, have prompted a reassessment, revealing fortresses in large villages like Sadovsko Kale. Procopius' account of Justinian's activities in Greece, part of Book IV, is not very detailed. He begins with
Thrace, mentioning in
Epirus the rebuilding of Nicopolis, the restoration of
Photice and Phoinike, and the construction of an unnamed city to which the inhabitants of Euroea were relocated; this city is typically identified as
Ioannina. After Epirus, Procopius moves to
Aetolia and Acarnania, but provides no specific details about constructions there. His account of
Thermopylae is relatively detailed. He then discusses central Greece and the
Peloponnese, noting that fortifications had long been in disrepair, but Justinian restored the walls of all cities, specifically naming
Corinth,
Athens, and
Plataea. To protect the entire peninsula, the
Isthmus of Corinth was fortified, possibly explaining why Procopius provides no further details about Peloponnesian cities. The narrative continues along the eastern coast, focusing more on
Thessaly, where he erroneously includes
Diocletianopolis. He mentions the reconstruction of fortifications at
Echinos,
Thebes,
Pharsalus,
Demetrias, and others. After discussing
Euboea, a
lacuna of unknown length interrupts the text, resuming with
Macedonia. Little is said about Macedonia—only the Long Wall across the
Pallene Peninsula, the rebuilding of
Cassandreia, and a fortress at the mouth of the
Axios River are mentioned. Analyzing the lists of geographical names in Book IV poses significant challenges. For instance, the list for Macedonia includes 46 names, only a few of which have been reliably identified. In 1974, English archaeologist Michael Vickers addressed the founding of
Thessaloniki, noting that, based on other written sources and archaeological data, Thessaloniki was established on the site of Therme, yet Therme appears in Procopius' list of Macedonian fortresses fortified under Justinian. One view holds that Procopius' data contradicts other sources, as fortifying Therme near Thessaloniki would have been pointless. Assuming the list is geographically ordered, Vickers concludes that Procopius' Therme was west of
Kavala, 165 km from Thessaloniki. Efforts have been made to verify Procopius' information. The most studied sections concern the fortifications of
Thermopylae and the
Isthmus of Corinth. Procopius highlights Justinian's foresight in building walls and fortresses, not relying on
chance. However, despite their detail, these accounts lack precise topographical information, with only the restored walls of
Corinth and
Hexamilion reliably located. Until excavations in the 1930s by
Spyridon Marinatos, skepticism prevailed about Procopius' topographical data on Thermopylae, based on 19th-century travelers' misconceptions. Excavations confirmed Justinian-era constructions, but later studies questioned or disproved such datings (e.g., for the walls of
Echinos and Nicopolis). Despite extensive excavations at Thermopylae and Hexamilion, including
radiocarbon dating, it is often confirmed that Procopius attributed to Justinian achievements from earlier reigns. Notably, Procopius omits religious constructions in Greece, despite evidence of significant Justinian-era churches, such as the large Basilica of Leonidas near
Corinth. Procopius' account of Greece was also compared with his other works and those of other authors. Thermopylae is mentioned in the Secret History regarding the reorganization of
Peloponnese defenses, where local peasants were replaced by 2,000 soldiers funded by public entertainment revenues, leading to neglected public buildings in "all of Greece, even
Athens," and an inability to undertake "other good deeds". In the same chapter, Procopius accuses Justinian of similar neglect across the empire, where "no one could care for public construction, and public lamps no longer burned in cities". The claim about theater closures is archaeologically unverifiable, and an early Justinian
novella encouraged performances. Numerous churches and public buildings were constructed in Greece under Justinian, though their funding sources are unknown. The restoration of
Corinth's walls is mentioned by
John Malalas, linked to repairs after the 521/522 earthquake, attributed to
Justin I's reign. However, the
Secret History attributes this and other earthquakes, as well as the
Plague of Justinian, to Justinian's demonic nature. Inscriptions on
Hexamilion stones praising Justinian are also known.
Book V: Asia Minor and Palestine in Ephesus. Various parts of
Asia Minor are covered in Books II, III, and V. The first two address the eastern frontiers, while Book V focuses on its main landmarks. After briefly mentioning the basilica dedicated to
John the Evangelist in
Ephesus, Procopius discusses notable granaries built on Justinian's orders on the island of
Tenedos. Located 15 km south of the
Dardanelles exit, the island was on the route of grain caravans from
Byzantine Egypt to
Constantinople. The granaries, "ninety feet wide, two hundred eighty feet long, and of inexpressible height", allowed ships to unload in a convenient harbor during strong headwinds and acquire goods for the return journey. Excavations for the granary on Tenedos have not been conducted, but available information does not contradict its existence. Justinian prioritized grain supply to the capital, as evidenced by his
edict of 538/539. However, similar granaries, built around 131 under Emperor
Hadrian in the
Lycian cities of
Patara and
Andriake, are known. If the Tenedos granary's height matched the Lycian ones, it was about 10 meters. Book V then describes cities along the
pilgrimage route through Asia Minor, starting in
Constantinople and passing through the
Bosporus,
Chalcedon,
Nicomedia,
Nicaea,
Ancyra,
Cappadocia, the
Cilician Gates,
Cilicia,
Syria, and
Palestine. To understand why Procopius' list begins with
Helenopolis in
Bithynia, one must consider the Secret History, where he accuses Justinian of destroying the
public road system, forcing travel from Chalcedon to
Dakibiza by sea. The Byzantine road between Helenopolis and Nicaea was identified by modern researchers, and Procopius' data on the Drakon River and its two bridges proved accurate. Among the typical praises, the mention of the Siberis River and the town of Sikeia, linked to
Theodore of Sykeon, is noteworthy. Until the late 20th century, Sikeia's location was unknown. Research in 1996 and 2001 resolved this, identifying structures described by Procopius and Theodore's hagiography. Regarding the
bridge over the Sangarius, beyond the dating issues discussed above, technical challenges arise. The bridge is now nearly 4 km from the
Sangarius, crossing a minor tributary called Melas in Byzantine times. Additionally, the bridge's
breakwater design differs from other known
Roman bridges. Despite the river flowing south to north, the breakwaters of all six piers are rounded to the south and pointed to the north. One theory suggests Justinian aimed to implement
Pliny the Younger's plan to connect
Lake Sapanca to the
Gulf of Nicomedia by redirecting the Sangarius. However, this project would have been impractical economically and geographically. According to
Michael Whitby, the breakwater design can be explained by the river's channel characteristics. The final three chapters of Book V detail Justinian's achievements in
Palestine, listing 22 projects of varying detail, including monasteries, churches, walls, charitable institutions, and wells. This list was likely compiled from
prefecture records in the 550s. It includes major projects like the wall in
Tiberias, as well as minor ones. The major reconstruction of the
Church of the Nativity is not mentioned, possibly because it occurred before or after the work's completion. Procopius provides the most detailed accounts for the
New Church in
Jerusalem, the church on Mount
Gerizim, and the
monastery on
Mount Sinai. The New Church, dedicated to the
Theotokos, is described first among Palestinian monuments. This account can be compared with a near-contemporary description by
Cyril of Scythopolis, whose protagonist is the monk
Sabbas the Sanctified. At his initiative, construction began under
Anastasius I, but remained incomplete by 531, when the 93-year-old Sabbas visited the court with financial requests for his ecclesiastical province. Sabbas' mission succeeded, securing funds to complete the church, which was consecrated 12 years later in 543. Cyril describes the construction circumstances but notes only its magnificence, inviting readers to see it themselves. In contrast, Procopius omits the early construction phase, names only Justinian among the builders, and details the structure's design. The New Church's location was unknown for a long time; its ruins were discovered in the mid-1970s in Jerusalem's
Jewish Quarter. This confirmed several of Procopius' claims, particularly about the unusually large foundation stones, averaging 4 tons, with some reaching 8.5 tons and over 2 meters in length—significant, though smaller than blocks in the
Temple Mount from the
Second Temple period. Procopius describes the challenges of transporting such large stones. While archaeologists found no direct evidence of a specially built road,
Nahman Avigad suggests the main Jerusalem street, the
Cardo, was completed in the 6th century. The interpretation of Procopius' description of columns "resembling the color of fire" is debated; Israeli archaeologist
Yoram Tsafrir suggests they may be made of
Jerusalem stone quarried nearby. Overall, Tsafrir argues that Justinian's reputation as Byzantium's greatest builder, at least in Jerusalem, is well-deserved.
Book VI: Africa Procopius' information on
Byzantine North Africa is a valuable complement to the limited archaeological data from the region. The book begins with a geographical description of the African provinces, divided into two after the separation of
Cyrenaica —
Upper Libya (or
Pentapolitan Libya) and Lower Libya. Unlike other books, Book VI lists relatively few structures. According to Procopius, five fortresses were built in Upper Libya and two in Lower Libya under Justinian, along with two churches and a restored
aqueduct in Upper Libya. Even less is reported for Lower Libya. The principle behind Procopius' selection of material in Africa is unclear. Many Byzantine fortresses are known in Libya, though few have been excavated, and many have been surveyed. Three fortresses mentioned by Procopius have been identified with some certainty:
Antipyrgon in Lower Libya, and
Teucheira and Boreum in Upper Libya. Without Procopius' references, the arguments for these identifications are less convincing. Some of his claims have sparked debate. His account of the complete reconstruction of the walls of Berenice and
Paratonium may reflect his tendency to exaggerate Justinian's achievements. Numerous observations on the dating of churches and military structures in Libya come from English archaeologist
Richard Goodchild. He suggests that many small fortresses near Boreum, using similar masonry, may date to the same period. Goodchild also proposed identifying a
Jewish settlement near Boreum, with a temple founded by King
Solomon, as Scina, also known as
Locus Judaeorum Augusti; this identification is not universally accepted. == Manuscripts and editions ==