Christianity in the Middle Ages in the context of "Way of St. James"

Greek East and Latin West are terms used to distinguish between the two parts of the Greco-Roman world and of Medieval Christendom, specifically the eastern regions where Greek was the lingua franca and the western parts where Latin filled this role.

Greek had spread as a result of previous Hellenization, whereas Latin was the official administrative language of the Roman state, stimulating Romanization. In the east, where both languages co-existed within the Roman administration for several centuries, the use of Latin ultimately declined as the role of Greek was further encouraged by administrative changes in the empire's structure between the 3rd and 7th centuries, which led to the split between the Eastern Roman Empire and the Western Roman Empire, the collapse of the latter, and failed attempts to restore unity by the former. This Greek–Latin divide continued with the East–West Schism of the Christian world during the Early Middle Ages.

Byzantine literature is the Greek literature of the Middle Ages, whether written in the Byzantine Empire or outside its borders. It was marked by a linguistic diglossy; two distinct forms of Byzantine Greek were used, a scholarly dialect based on Attic Greek, and a vernacular based on Koine Greek. Most scholars consider 'literature' to include all medieval Greek texts, but some define it with specific constraints. Byzantine literature is the successor to Ancient Greek literature and forms the basis of Modern Greek literature, although it overlaps with both periods.

The tradition saw the competing influences of Hellenism, Christianity, and earlier in the empire's history, Paganism. There was a general flourishing of gnomai, hagiography, sermons, and particularly historiography, which became less individual-focused. Poetry was often limited to musical hymnal forms, or the more niche epigram tradition, while ancient dramas and epics became obsolete. The influential romantic epic Digenes Akritas is a major exception.

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 Suda or Souda (/ˈsuːdə/; Medieval Greek: Σοῦδα Soûda [ˈsuða]; Latin: Suidae Lexicon) is a large 10th-century Byzantine encyclopedia of the ancient Mediterranean world, formerly attributed to an author called Soudas (Σούδας) or Souidas (Σουίδας). It is an encyclopedic lexicon, written in Greek, with 30,000 entries, many drawing from ancient sources that have since been lost, and often derived from medieval Christian compilers.

The Holy Roman Emperor, originally and officially the Emperor of the Romans (Latin: Imperator Romanorum; German: Kaiser der Römer) during the Middle Ages, and also known as the Roman-German Emperor since the early modern period (Latin: Imperator Germanorum; German: Römisch-Deutscher Kaiser), was the ruler and head of state of the Holy Roman Empire. The title was held in conjunction with the title of King of Italy (Rex Italiae) from the 8th to the 16th century, and, almost without interruption, with the title of King of Germany (Rex Teutonicorum, lit. 'King of the Teutons') throughout the 12th to 18th centuries.

The Holy Roman Emperor title provided the highest prestige among medieval Catholic monarchs, because the empire was considered by the Catholic Church to be the only successor of the Roman Empire during the Middle Ages and the early modern period. Thus, in theory and diplomacy, the emperors were considered primus inter pares—first among equals—among other Catholic monarchs across Europe.

Septimania is a historical region in modern-day southern France. It referred to the western part of the Roman province of Gallia Narbonensis that passed to the control of the Visigoths in 462, when Septimania was ceded to their king, Theodoric II. During the Early Middle Ages, the region was variously known as Gallia Narbonensis, Gallia, or Narbonensis. The territory of Septimania roughly corresponds with the modern French former administrative region of Languedoc-Roussillon that merged into the new administrative region of Occitanie. In the Visigothic Kingdom, which became centred on Toledo by the end of the reign of Leovigild, Septimania was both an administrative province of the central royal government and an ecclesiastical province whose metropolitan was the Archbishop of Narbonne. Originally, the Goths may have maintained their hold on the Albigeois, but if so it was conquered by the time of Chilperic I. There is archaeological evidence that some enclaves of Visigothic population remained in Frankish Gaul, near the Septimanian border, after 507.

The region of Septimania was invaded by the Andalusian Muslims in 719, renamed as Arbūnah and turned into a military base for future operations by the Andalusian military commanders. It passed briefly to the Emirate of Córdoba, which had been expanding from the south during the same century, before its subsequent conquest by the Christian Franks in 759, who by the end of the 9th century renamed it as Gothia or the Gothic March (Marca Gothica). Eventually, the Christian Franks chased the Muslim Arabs and Berbers away from Septimania and conquered Narbonne in 759, and the Carolingian king Pepin the Short came up reinforced. Septimania became a march of the Carolingian Empire and then West Francia down to the 13th century, though it was culturally and politically autonomous from the northern France-based central royal government. The region was under the influence of the people from the count territories of Toulouse, Provence, and ancient County of Barcelona. It was part of the wider cultural and linguistic region comprising the southern third of France known as Occitania. This area was finally brought under effective control of the French kings in the early 13th century as a result of the Albigensian Crusade, after which it was assigned governors. From the end of the thirteenth century Septimania evolved into the royal province of Languedoc.

The Camino de Santiago (Latin: Peregrinatio Compostellana, lit. 'Pilgrimage of Compostela'; Galician: O Camiño de Santiago), or the Way of St. James in English, is a network of pilgrims' ways or pilgrimages leading to the shrine of the apostle James in the cathedral of Santiago de Compostela in Galicia in northwestern Spain, where tradition holds that the remains of the apostle are buried. Pilgrims follow its routes as a form of spiritual path or retreat for their spiritual growth. It is also popular with hikers, cyclists, and organized tour groups.

Created and established in the beginning of the 9th century following the discovery of the relics of Saint James the Great, the Way of St. James became a major pilgrimage route of medieval Christianity from the 10th century onwards. Following the end of the Granada War in 1492, under the reign of the Catholic Monarchs Ferdinand II of Aragon and Isabella I of Castile, Pope Alexander VI officially declared the Camino de Santiago to be one of the "three great pilgrimages of Christendom", along with Jerusalem and the Via Francigena to Rome.

The Holy Lance, also known as the Spear of Longinus (named after Saint Longinus), the Spear of Destiny, or the Holy Spear, is alleged to be the lance that pierced the side of Jesus as he hung on the cross during his crucifixion. As with other instruments of the Passion, the lance is only briefly mentioned in the Christian Bible, but later became the subject of extrabiblical traditions in the medieval church. Relics purported to be the lance began to appear as early as the 6th century, originally in Jerusalem. By the Late Middle Ages, relics identified as the spearhead of the Holy Lance (or fragments thereof) had been described throughout Europe. Several of these artifacts are still preserved to this day.

Holy Lance relics have typically been used for religious ceremonies, but at times some of them have been considered to be guarantees of victory in battle. For example, Henry the Fowler's lance was credited for winning the Battle of Riade, and the Crusaders believed their discovery of a Holy Lance brought them a favorable end to the Siege of Antioch.