Basilica of San Vitale in the context of "Bartholomew the Apostle"

Cathedrals, collegiate churches, and monastic churches like those of abbeys and priories, often have certain complex structural forms that are found less often in parish churches. They also tend to display a higher level of contemporary architectural style and the work of accomplished craftsmen, and occupy a status both ecclesiastical and social that an ordinary parish church rarely has. Such churches are generally among the finest buildings locally and a source of regional pride. Many are among the world's most renowned works of architecture. These include St Peter's Basilica, Notre-Dame de Paris, Cologne Cathedral, Salisbury Cathedral, Antwerp Cathedral, Prague Cathedral, Lincoln Cathedral, the Basilica of Saint-Denis, Santa Maria Maggiore, the Basilica of San Vitale, St Mark's Basilica, Westminster Abbey, Saint Basil's Cathedral, Antoni Gaudí's incomplete Sagrada Família and the ancient cathedral of Hagia Sophia in Istanbul, now a mosque.

The earliest large churches date from Late Antiquity. As Christianity and the construction of churches spread across the world, their manner of building was dependent upon local materials and local techniques. Different styles of architecture developed and their fashion spread, carried by the establishment of monastic orders, by the posting of bishops from one region to another and by the travelling of master stonemasons who served as architects. The successive styles of the great church buildings of Europe are known as Early Christian, Byzantine, Romanesque, Gothic, Renaissance, Baroque, Rococo, Neoclassical, and various Revival styles of the late 18th to early 20th centuries, and then Modern. Underlying each of the academic styles are the regional characteristics. Some of these characteristics are so typical of a particular country or region that they appear, regardless of style, in the architecture of churches designed many centuries apart.

The Byzantine Papacy was a period of Byzantine domination of the Roman Papacy from 537 to 752, when popes required the approval of the Byzantine Emperor for their episcopal consecration, and many popes were chosen from the apocrisiarii (liaisons from the pope to the emperor) or the inhabitants of Byzantine-ruled Greece, Syria, or Sicily. Justinian I reconquered the Italian peninsula in the Gothic War (535–554) and appointed the next three popes, a practice that would be continued by his successors and later be delegated to the Exarchate of Ravenna.

With the exception of Martin I, no pope during this period questioned the authority of the Byzantine monarch to confirm the election of the bishop of Rome before consecration could occur; however, theological conflicts were common between pope and emperor in the areas such as monothelitism and iconoclasm.

John the Apostle (Ancient Greek: Ἰωάννης; Latin: Ioannes; c. 6 AD – c. 100 AD), also known as Saint John the Beloved and, in Eastern Orthodox Christianity, Saint John the Theologian, was one of the Twelve Apostles of Jesus according to the New Testament. Generally listed as the youngest apostle, he was the son of Zebedee and Salome. His brother James was another of the Twelve Apostles. The Church Fathers identify him as John the Evangelist, John of Patmos, John the Elder, and the Beloved Disciple, and claim that he outlived the remaining apostles and was the only one to die of natural causes, although modern scholars are divided on the veracity of these claims.

John the Apostle is traditionally held to be the author of the Gospel of John, and many Christian denominations believe that he authored several other books of the New Testament (the three Johannine epistles and the Book of Revelation, together with the Gospel of John, are called the Johannine works), depending on whether he is distinguished from, or identified with, John the Evangelist, John the Elder, and John of Patmos.

Thomas the Apostle (Greek: Θωμᾶς, romanized: Thōmâs; Classical Syriac: ܬܐܘܡܐ, romanized: Tʾōmā, meaning 'the Twin'), also known as Didymus (Greek: Δίδυμος, romanized: Dídymos 'twin'), was one of the Twelve Apostles of Jesus according to the New Testament. Thomas is commonly known as "doubting Thomas" because he initially doubted the resurrection of Jesus when he was told of it (as is related in the Gospel of John); he later confessed his faith ("The lord of me and the God of me") on seeing the places where the wounds appeared still fresh on the holy body of Jesus after the Crucifixion of Jesus.

According to traditional accounts of the Saint Thomas Christians of Kerala, Thomas travelled outside the Roman Empire to preach the Gospel, traveling through southern India in the modern states of Kerala and Tamil Nadu, and eventually reached Muziris (modern-day North Paravur and Kodungalloor) in 52 AD. He started the Church of the East in the region around the Van Province, Edessa, and Hakkari regions of Upper Mesopotamia (modern-day southeastern Turkey), presumably sometime between mid-late 30s and 45, and spent many years evangelizing both Jews and pagans in the area before heading further east in the late 40s. In 1258, some of the relics were brought to Ortona, in Abruzzo, Italy, where they have been held in the Church of Saint Thomas the Apostle. He is regarded as the patron saint of India among its Christian adherents, and the Feast of Saint Thomas on July 3 is celebrated as Indian Christians' Day. The name Thomas remains quite popular among the Saint Thomas Christians of the Indian subcontinent.

The tablion (Greek: ταβλίον) was a rectangular or trapezoidal panel embroidered on the ceremonial mantle (chlamys) of courtiers during the Byzantine Empire.

The tablia were chosen to contrast with the mantle colour, and sewn pairwise on the front edges of the mantle. They could be further decorated with embroidered designs or images of the emperor. The emperor's mantle originally (in the 4th century) featured tablia sewn almost at the bottom of the mantle, below the knees, but from the 6th century they were moved to the centre of the mantle opening. As the chlamys was the chief civilian court dress, the tablion was a part of male court costume, and had to be purchased by the office-holders (for example, a patrikios paid 24 gold solidi in the 9th century). The only women allowed to wear a chlamys and tablion were the empresses. In the middle Byzantine period, the chlamys is much more richly decorated, but is sometimes depicted without tablia. The exact significance of this is unclear, although it has been suggested that it might denote lower court ranks.

The Battle of Mons Lactarius (also known as Battle of the Vesuvius) took place in 552 or 553 AD during the Gothic War (535–554) between Byzantine forces and the Ostrogoths (Goths) near Mount Vesuvius in Italy.

Byzantine forces, led by General Narses confronted the army of the Gothic King Teias in the rugged terrain near Mount Vesuvius. After two months of stalemate, the two sides finally engaged in open battle. Teias was killed in the fighting, marking the collapse of Gothic leadership. The remaining Gothic troops resisted for a short time but ultimately surrendered under negotiated terms. This victory ended Gothic power on the Italian peninsula, allowing the Byzantines to reestablish their authority there.

James, son of Alphaeus (Greek: Ἰάκωβος, Iakōbos; Aramaic: ܝܥܩܘܒ ܒܪ ܚܠܦܝ; Hebrew: יעקב בן חלפי Ya'akov ben Halfai; Coptic: ⲓⲁⲕⲱⲃⲟⲥ ⲛⲧⲉ ⲁⲗⲫⲉⲟⲥ; Arabic: يعقوب بن حلفى, romanized: Ya'qūb bin Halfā) was one of the Twelve Apostles of Jesus, appearing under this name in all three of the Synoptic Gospels' lists of the apostles. He is generally identified with James the Less (Ancient Greek: Ἰάκωβος ὁ μικρός Iakōbos ho mikros, Mark 15:40) and commonly known by that name in church tradition. He is also labelled "the Minor", "the Little", "the Lesser", or "the Younger", according to translation. He is distinct from James, son of Zebedee and in some interpretations also from James, brother of Jesus (James the Just). He appears only four times in the New Testament, each time in a list of the twelve apostles.