The architecture of the Byzantine Empire at its outset was essentially that of the Late Roman Empire from which it emerged in the early fourth century CE. Administrative and commercial affairs were run from cities large and small that were spread around the vast empire, many of them on or near the coasts of the Mediterranean, Aegean, and Black seas, for the convenience of transport by water. The city was a place of well-ordered architecture: wide paved streets, the chief ones lined with porticos, intersected at open spaces that were the centers of commercial and public life, often embellished with monumental arches and statues on columns and pedestals. Lining many streets were insulae, terraced apartments in which shopkeepers and artisans conducted their trades on the ground floor and lived on the upper one. The ruling class lived in urban mansions or palaces and governed from fine civic buildings, and most citizens enjoyed the comforts of piped water and drainage, fountains, pools and bath houses with under-floor heating, even flushed latrines; the water was often delivered from sources outside the city by aqueducts and stored in cisterns. Citizens could also enjoy the entertainments available in the theater, arena, and hippodrome.
All these facilities were present in the early fourth century refurbishment of Constantinople by Constantine I, where they are known largely from documentary sources rather than material remains. Elsewhere, such continuity with the late Roman tradition was often a matter of maintenance rather than new building, following the decline in the wealth and power of the empire from the third century. There was, however, new activity in two areas of architecture, those of security and religion. Invasion and raiding by barbarian neighbors encouraged the building of city walls, a process that was general by the fourth century. Constantine's work in Constantinople included extension of Roman sea walls and construction of a land wall to enclose the city on its promontory site; a century later, Theodosius II(408–50) built the massive land wall to enclose a larger area with space for reservoirs to improve water conservation in the city. In the sixth century, Anastasios I (430–518) and Justinian I (527–65) attempted to secure the empire's border defenses, from the Danube to Mesopotamia, with forts, walls, and towers, occasionally combining defense with other functions, as in the case of the massively fortified monastery at the foot of Mount Sinai (later known as St. Catherine's).
However, the most conspicuous new construction (and architectural innovation) of the early Byzantine Empire was that which served religion. The imperial sanction of Christianity by Constantine i did not cause paganism to vanish overnight, but pagan temples, especially those in public places, steadily disappeared. some were converted to Christian use and others were destroyed, to be replaced by Christian churches, a gesture of obvious symbolism; the good-quality stones, columns, and capitals of destroyed or abandoned temples were often reused in walls. in tandem with this the architecture of Christianity became increasingly more evident: documentary sources indicate that church architecture was established before the time of Constantine i, but with imperial backing the scale increases and churches appear as additions to the fabric of many of the cities in use since late Roman times. Church building was also a means of stamping the new order on the empire: using his mother Helena as his agent, Constantine i commissioned the building of large churches at the Christian holy places of Palestine, notably at the sites of the Nativity of Christ in Bethlehem and the Holy Sepulcher in Jerusalem. In the fifth century, similarly grand churches were built at sites that became places of pilgrimage for the Christians of their regions, often in or close to major centers of population and associated with the relics of early Christian saints, such as St. Demetrios in Thessalonike (see Demetrios (Saint)) and Qal'at Sem'an northeast of Antioch.
These churches were large timber-roofed basilicas divided longitudinally into nave and aisles by colonnades, a form derived from the rectangular halls of Roman secular architecture; by the fifth century the basilica was an empire-wide standard type for churches, and it is not until the early sixth century that there is radical change in design, using domed vaulting (see Church architecture). There must also have been steadily increasing construction of more modest churches and chapels to serve the growing christian population, especially of small basilicas and timber-roofed or barrelvaulted single-naved structures, but of these there are very few survivals. Baptisteries, usually octagonal, were associated with many churches, and some also had mausolea for their founders. There is evidence from the fifth century of buildings for the monastic communities, some of them very large, that were established in Palestine, syria, Egypt, and Anatolia. Most of these were essentially villages enclosed within a perimeter wall, but the sinai monastery noted above has what becomes the conventional scheme for the Byzantine monastery: a walled enclosure, with domestic buildings, work rooms, and storage rooms built up against the walls, enclosing a courtyard that has in it a free-standing church.
Justinian i, the last emperor to rule an empire of Roman proportions, was also the last great builder: his historian Procopius takes an entire book to catalogue his architectural commissions both secular and religious, albeit with some exaggeration in places. Towards the end of the sixth century there was territorial erosion on all sides, and by the end of the seventh century the rise of islam had brought the devastating loss of most of Anatolia - Arabs twice besieged Constantinople (674–8 and 717/18). Partial recovery was achieved in the ninth century, but two centuries of such disruption broke the traditional transmission of technology from one generation to the next. From the ninth century onwards, Byzantine builders could keep some of the grand old buildings and fortifications in repair, but lacked the refined technical knowledge and skills that had built them; their buildings were smaller and, although often elegant, of generally simpler construction.
Arena; Basilica; Building materials and techniques, Byzantine; Constantine I; Hippodromes; Martyrion; Monasteries, in the east; Theater, Greek and Roman.
Architectural Features of Byzantine Churches With the legalization of Christianity came imperial patronage in the realm of church art. Emperor Co
Byzantine construction materials and techniques of the fourth to sixth centuries CE continue Roman traditions. Cut blocks of limestone or sandstone
There are so few material remains of Byzantine palaces that they must be largely reconstructed from documentary sources and analogy with buildings o