Exarchate of Ravenna in the context of "Byzantine Papacy"

The Republic of Venice, officially the Most Serene Republic of Venice and traditionally known as La Serenissima, was a sovereign state and maritime republic with its capital in Venice. Founded, according to tradition, in 697 by Paolo Lucio Anafesto, over the course of its 1,100 years of history it established itself as one of the major European commercial and naval powers. Initially extended in the Dogado area (a territory currently comparable to the Metropolitan City of Venice), during its history it annexed a large part of Northeast Italy, Istria, Dalmatia, the coasts of present-day Montenegro and Albania as well as numerous islands in the Adriatic and eastern Ionian seas. At the height of its expansion, between the 13th and 16th centuries, it also governed Crete, Cyprus, the Peloponnese, a number of Greek islands, as well as several cities and ports in the eastern Mediterranean.

The islands of the Venetian Lagoon in the 7th century, after having experienced a period of substantial increase in population, were organized into Maritime Venice, a Byzantine duchy dependent on the Exarchate of Ravenna. With the fall of the Exarchate and the weakening of Byzantine power, the Duchy of Venice arose, led by a doge and established on the island of Rialto; it prospered from maritime trade with the Byzantine Empire and other eastern states. To safeguard the trade routes, between the 9th and 11th centuries the Duchy waged several wars, which ensured its complete dominion over the Adriatic. Owing to its participation in the Crusades, Venice increasingly penetrated into eastern markets and, between the 12th and 13th centuries, managed to extend its power into numerous eastern emporiums and commercial ports. The supremacy over the Mediterranean Sea led the Republic to the clash with Genoa, which lasted until the 14th century, when, after having risked complete collapse during the War of Chioggia (with the Genoese army and fleet in the lagoon for a long period), Venice quickly managed to recover from the territorial losses suffered with the Treaty of Turin of 1381 and begin expansion on the mainland.

The history of Italy in the Middle Ages can be roughly defined as the time between the collapse of the Western Roman Empire and the Italian Renaissance. Late antiquity in Italy lingered on into the 7th century under the Ostrogothic Kingdom and the Byzantine Empire under the Justinian dynasty, the Byzantine Papacy until the mid 8th century. The "Middle Ages" proper begin as the Byzantine Empire was weakening under the pressure of the Muslim conquests, and most of the Exarchate of Ravenna finally fell under Lombard rule in 751. From this period, former states that were part of the Exarchate and were not conquered by the Lombard Kingdom, such as the Duchy of Naples, became de facto independent states, having less and less interference from the Eastern Roman Empire.

Lombard rule ended with the invasion of Charlemagne in 773, who established the Kingdom of Italy and the Papal States in large parts of Northern and Central Italy. This set the precedent for the main political conflict in Italy over the following centuries, between the Pope and the Holy Roman Emperor, culminating with conflict between Pope Gregory VII and Henry IV and the latter's "Walk to Canossa" in 1077.

Ravenna (/rəˈvɛnə/ rə-VEN-ə; Italian: [raˈvenna], also locally [raˈvɛn(n)a] ; Romagnol: Ravèna, Ravêna) is the capital city of the Province of Ravenna, in the Emilia-Romagna region of Northern Italy. It was the capital city of the Western Roman Empire during the 5th century until its collapse in 476, after which it served as the capital of the Ostrogothic Kingdom and then the Byzantine Exarchate of Ravenna. It has 156,444 inhabitants as of 2025.

Initially settled by the Umbri people, Ravenna came under Roman Republic control in 89 BC. Octavian built the military harbor of Classis at Ravenna, and the city remained an important seaport on the Adriatic until the early Middle Ages. The city prospered under imperial rule. In 401, Western Roman emperor Honorius moved his court from Mediolanum to Ravenna; it then served as capital of the empire for most of the 5th century.

The Papal States (/ˈpeɪpəl/ PAY-pəl; Italian: Stato Pontificio; Latin: Dicio Pontificia), officially the State of the Church, were a conglomeration of territories on the Italian peninsula under the direct sovereign rule of the pope from 756 to 1870. They were among the major states of Italy from the 8th century until the unification of Italy, which took place between 1859 and 1870, culminating in their demise.

The state was legally established in the 8th century when Pepin the Short, king of the Franks, gave Pope Stephen II, as a temporal sovereign, lands formerly held by Arian Christian Lombards, adding them to lands and other real estate formerly acquired and held by the bishops of Rome as landlords from the time of Constantine onward. This donation came about as part of a process whereby the popes began to turn away from the Byzantine emperors as their foremost temporal guardians for reasons such as increased imperial taxes, disagreement with respect to iconoclasm, and failure of the emperors, or their exarchs in Italy, to protect Rome and the rest of the peninsula from barbarian invasion and pillage.

Byzantine Venetia (Greek: Bενετικὰ, romanized: Venetikà), also known as the Byzantine Maritime Venetia (Latin: Venetia maritima), or Maritime Venice (Italian: Venezia marittima), was a territory of the Byzantine Empire, within the Exarchate of Ravenna, that existed from the middle of the 6th century, up to the second half of the 7th century. Its territory was corresponding to the coastal belt of ancient Venetia and Istria, encompassing coastal regions of present-day Veneto, and Friuli-Venezia Giulia, including the Venetian Lagoon. Its territory did not include hinterland of the old Venetian province, which was conquered by the Lombards. Within Byzantine domains in Italy, Maritime Venetia had a peripheral position, characterized by a patchwork of settlements without major urban centers, besides Oderzo (Latin: Opitergium), the capital city of the province.

In the year before the First Council of Constantinople in 381, Nicene Christianity became the official religion of the Roman Empire when Theodosius I, emperor of the East, Gratian, emperor of the West, and Gratian's junior co-ruler Valentinian II issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy, as defined by the Council of Nicea, as the Roman Empire's state religion. Historians refer to this state-sponsored church using a variety of terms: the catholic church, the orthodox church, the imperial church, the Roman church, or the Byzantine church, with some also used for wider communions extending beyond the Roman Empire. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church all claim to stand in continuity from the Nicene Christian church to which Theodosius granted recognition. Political differences between the Eastern Roman Empire and the Persian Sassanid Empire led to the separation of the Church of the East in 424. A doctrinal split within the imperial church led to the independence of early Oriental Orthodoxy, while the fall of the Western Roman Empire initiated the gradual separation between Eastern and Western Christianity, culminating in the East-West schism of 1054. The Western Church evolved into the Latin Catholic Church while the Eastern Church that remained under the patronage of the Eastern empire and evolved into the Greek Orthodox Church.

Earlier in the 4th century, following the Diocletianic Persecution of 303–313 and the Donatist controversy that arose in consequence, Constantine the Great had convened councils of bishops to define the orthodoxy of the Christian faith and to expand on earlier Christian councils. A series of ecumenical councils convened by successive Roman emperors met during the 4th and the 5th centuries, but Christianity continued to suffer rifts and schisms surrounding the theological and christological doctrines of Arianism, Nestorianism, Miaphysitism, and Dyophysitism. In the 5th century, the Western Roman Empire decayed as a polity; invaders sacked Rome in 410 and in 455, and Odoacer, an Arian barbarian warlord, forced Romulus Augustus, the last nominal Western Emperor, to abdicate in 476. However, apart from the aforementioned schisms, the church as an institution persisted in communion, if not without tension, between the East and West. In the 6th century, the Byzantine armies of the Byzantine Emperor Justinian I recovered Italy and other regions of the Western Mediterranean shore. The Byzantine Empire soon lost most of these gains, but it held Rome, as part of the Exarchate of Ravenna, until 751, a period known in church history as the Byzantine Papacy. The early Muslim conquests of the 7th–9th centuries would begin a process of converting most of the then-Christian world in the Levant, Middle East, North Africa, regions of Southern Italy and the Iberian Peninsula to Islam, severely restricting the reach both of the Byzantine Empire and of its church. Christian missionary activity directed from the capital of Constantinople did not lead to a lasting expansion of the formal link between the church and the Byzantine emperor, since areas outside the Byzantine Empire's political and military control set up their own distinct churches, as in the case of Bulgaria in 919.

The Duchy of Rome (Latin: Ducatus Romanus; Greek: Δουκᾶτον Ῥώμης, romanized: Doukâton Rhṓmēs) was a state within the Byzantine Exarchate of Ravenna. Like other Byzantine states in Italy, it was ruled by an imperial functionary with the title of dux. The duchy often came into conflict with the Papacy over supremacy within Rome. After the founding of the Papal States in 756, the Duchy of Rome ceased to be an administrative unit and "dukes of Rome", appointed by the popes rather than emperors, are only rarely attested.

Neo-Byzantine architecture (also referred to as Byzantine Revival) was a revival movement, most frequently seen in religious, institutional and public buildings. It incorporates elements of the Byzantine style associated with Eastern and Orthodox Christian architecture dating from the 5th through 11th centuries, notably that of Constantinople (present-day Istanbul) and the Exarchate of Ravenna.

Neo-Byzantine architecture emerged in the 1840s in Western Europe and peaked in the last quarter of the 19th century with the Sacré-Coeur Basilica in Paris, and with monumental works in the Russian Empire, and later Bulgaria. The Neo-Byzantine school was active in Yugoslavia in the interwar period.