East Roman Empire in the context of "State religion"

The Western world, also known as the West, primarily refers to various nations and states in Western Europe, Northern America, and Australasia; with some debate as to whether those in Eastern Europe and Latin America also constitute the West. The Western world likewise is called the Occident (from Latin occidens 'setting down, sunset, west') in contrast to the Eastern world known as the Orient (from Latin oriens 'origin, sunrise, east'). Definitions of the "Western world" vary according to context and perspectives; the West is an evolving concept made up of cultural, political, and economic synergy among diverse groups of people, and not a rigid region with fixed borders and members.

Some historians contend that a linear development of the West can be traced from Ancient Greece and Rome, while others argue that such a projection constructs a false genealogy. A geographical concept of the West started to take shape in the 4th century CE when Constantine, the first Christian Roman emperor, divided the Roman Empire between the Greek East and Latin West. The East Roman Empire, later called the Byzantine Empire, continued for a millennium, while the West Roman Empire lasted for only about a century and a half. Significant theological and ecclesiastical differences led Western Europeans to consider the Christians in the Byzantine Empire as heretics. In 1054 CE, when the church in Rome excommunicated the patriarch of Byzantium, the politico-religious division between the Western church and Eastern church culminated in the Great Schism or the East–West Schism. Even though friendly relations continued between the two parts of Christendom for some time, the crusades made the schism definitive with hostility. The West during these crusades tried to capture trade routes to the East and failed, it instead discovered the Americas. In the aftermath of the European colonization of the Americas, primarily involving Western European powers, an idea of the "Western" world, as an inheritor of Latin Christendom emerged. According to the Oxford English Dictionary, the earliest reference to the term "Western world" was from 1586, found in the writings of William Warner.

The praetorian prefecture (Latin: praefectura praetorio; in Greek variously named ἐπαρχότης τῶν πραιτωρίων or ὑπαρχία τῶν πραιτωρίων) was the largest administrative division of the late Roman Empire, above the mid-level dioceses and the low-level provinces. Praetorian prefectures originated in the reign of Constantine I (r. 306–337), reaching their more or less final form in the last third of the 4th century and surviving until the 7th century, when the reforms of Heraclius diminished the prefecture's power, and the Muslim conquests forced the Eastern Roman Empire to adopt the new theme system. Elements of the prefecture's administrative apparatus, however, are documented to have survived in the Byzantine Empire until the first half of the 9th century.

Roman Armenia refers to the rule of parts of Greater Armenia by the Roman Empire from the 1st century AD to the end of Late Antiquity. While Armenia Minor had become a client state until it was incorporated into the Roman Empire proper during the 1st century AD, Greater Armenia remained an independent kingdom under the Arsacid dynasty. Throughout this period, Armenia remained a bone of contention between Rome and the Parthian Empire, as well as the Sasanian Empire that succeeded the latter, and the casus belli for several of the Roman–Persian Wars. Only in 114 would Emperor Trajan conquer and incorporate it as a short-lived Roman province.

In the late 4th century, Armenia was divided between Rome and the Sasanians, who took control of the larger part of the Armenian Kingdom and, in the mid-5th century, abolished the Armenian monarchy. In the 6th and the 7th centuries, Armenia once again became a battleground between the East Roman Empire (Byzantine) and the Sasanian Empire until both powers were defeated and replaced by the Muslim Caliphate in the mid-7th century.

The Ponte Salario, also called Ponte Salaro during the Middle Ages, is a road bridge in Rome, Italy, whose origins date back to the Roman period. In antiquity, it lay outside the city limits, 3 km north of the Porta Collina, at the point where the Via Salaria (modern SS4) crossed the Aniene, a tributary of the Tiber. The visible side arches are assumed to originate from the first stone structure built during the 1st century BC.

In the Gothic War (535–554), the main arch was largely destroyed by the Ostrogothic king Totila, but repaired by his East Roman opponent Narses in 565, who recorded the extensive restoration works, including a river diversion, in an extant bridge inscription. At that time, the Ponte Salario was 72 m long and 6.52 m wide, with its semi-circular arch reaching a remarkable clear span of 24.86 m.