abstract: A style laying emphasis on abstraction, transcendental perception and spirituality. The compositions are two-dimensional and linear while depth is rendered simply. Figures are depicted frontally and appear immaterial, and faces are given austere and ascetic expressions.

Acheiropoietos ('not made by hands'): The icon that according to Holy Tradition was not the product of human hands but rather of some miracle.

aerikon or aer: Supplementary or extraordinary taxation. It had two different senses: first, it was a fine for an offense, collected by a clergyman or tax collector, and, secondly, a supplementary tax of 4-20 nomismata imposed on a village.

aerokratikon: Tax due given to the collector of the aerikon.

Aetios: A physician (born in Amida) who lived in Constantinople and Alexandria in the middle of the 6th century. He wrote a medical encyclopaedia consisting of 16 books divided into four sections - hence the name 'Tetrabiblon' (Four-Books). This work is important mainly for the careful selection of passages written by ancient authorities and for its attempt to combine traditional and contemporary medical theory.

agridion ('hamlet'): The usual allotment of land in the countryside.

aisle: The section of the main area of the church that is defined by the internal series of pillars or columns that supported the roof.

Akathistos ('not seated') Hymn: An encomiastic hymn in honour of the Virgin Mary chanted (standing) during Lent. According to tradition it was written in order to invoke the intervention of the Virgin when Constantinople was attacked by the Avars and the Persians in 626.

Akolouthia ('succession'): The specific order of the orations and the acts of prayers or liturgy in the Christian Church.

akritai: A term encountered in Byzantine military treatises of the 10th and the 11th century denoting the inhabitants and defenders of Byzantium΄s eastern borders. The exploits of the akritai against the Muslims inspired the well-known epic poem Digenes Akritas.

aktemon ('without property'): Fiscal description of a peasant not possessing land or animals for agricultural labour. The sole belongings such a peasant could have were a small vineyard or croft, but certainly not any animals for stockbreeding (as for example goats, sheeps or bees). The term appears for the first time in written sources from 1073.

Alexander of Tralles: Physician born in Tralles in 525 and who died in Rome in 605, brother of Hagia Sophia΄s architect, Anthemios. The 12-book medical encyclopaedia he wrote shows a humane and enthusiastic approach to medicine, as well as sensitivity and an open mind towards medical practice in general and towards the treatment of patients.

Alexandria: The third largest city in Late Roman and Early Byzantine times, located in Lower Egypt. It was the administrative, military, ecclesiastical, manufacturing and commercial centre of the region. Products were traded from its two ports from and to the whole of the eastern Mediterranean, Upper Egypt (via Nile) and the West. It was also the biggest cultural centre in the East, a function it retained until very recently.

Aristenos Alexios: One of the three great Byzantine canonists of the 12th century (the other two being Balsamon and Zonaras). On the command of the Emperor John II Komnenos (1118-1143) he wrote comments (scholia) on the 'Synopsis Canon' ascribed to Symeon Metaphrastes (10th century).

Αl-Ma'mun: Abbassid caliph from 813 to 833. He fostered the study of classical Greek works, especially philosophy and science, and thus enriched the vigorous cultural life of the caliphate.

Amalfi: An independent Tyrrhenean port in southern Italy. From the 9th century onwards many of its citizens were actively engaged in trade, reaching from the Mediterranean as far as Egypt, the Maghreb and Spain. They set up colonies in Dyrrachion, Antioch as well as in Constantinople where they founded a monastery dedicated to the Virgin Mary.

Amorion: Modern Hisar, located near Emirdag on the borders of Galatia and Phrygia in central Asia Minor. It became an important city from the 7th century, when it became the capital of the Armeniakon Theme due to its strategic position on the main raiding routes from the south.

Anatolia: Another name for Asia Minor, the western part of the Asiatic continent.

Angeloi: Byzantine family of lowly origin that came to the fore due to the handsome Constantinos Angelos who married the daughter of Alexios I, Theodora. In the 12th century some Angeloi stood out as military commanders, while in 1185 one of them, Isaac II, became Emperor, founding the last dynasty before the fall of Constantinople at the hands of the Latins in 1204. After 1204 the Angeloi imposed their power in Epiros and Thessalonike, initially as independent sovereigns and later as imperial officers.

angle chambers: The four basic corner areas in the rectangular ground plan of a church. The angle chambers are situated around the arms of the cross, supporting the church's dome.

Ani: An important city, strategically located in northeast Asia Minor. It enjoyed great prosperity as an administrative and commercial centre and became capital of Armenia in 961. It was known as 'the city with the 1001 churches'.

Anna Dalassene (1025-1100 or 1102): Mother of Alexios I Komnenos. During his campaigns Alexios vested her with wide powers of administrative jurisdiction. When her relations with Alexios were marred due to charges of maladministration, she retired to the Pantepoptes Christ monastery.

anonymous teacher: Name given to a man who lived in the early days of the 10th century but whose name remains unknown. He was very likely born in Thrace circa 870, was a secondary teacher and scribe in Constantinople in the 920s. 122 of his epistles are extant in a sole manuscript of the late 10th century, giving us a picture of his activity as well as of the educational system of the age.

apocryphal gospels: Religious texts not officialy accepted by the Church. These texts were a source of inspiration for Byzantine artists. A characteristic example is the Protoevangelion of James, referring to the life of the Virgin and the childhood of Jesus.

apse: Semicylindrical recess on the eastern side of the church, reserved for the clergy and shut off from the rest of the church by closure or screen.

Apsimaros - Tiberios II: Byzantine Emperor (698-705). He was a droungarios (admiral) of the Kibyrrhaiotai Theme and after the mutiny of the army and fleet against the Emperor Leontios he was proclaimed Emperor and renamed Tiberios. During his reign, Byzantine troops won several victories in the East. After his overthrow by Justinian II, he was pilloried, along with his predecessor Leontios, and decapitated.

Arabs of Africa: Arabs from Tunisia and surrounding areas who in the 9th century dominated the central Mediterranean and conquered Sicily.

Arabs of the West: The Arabs who in 711 under the leadership of Tariq crossed the straits that subsequently took his name (Gibraltar = gibel al Tariq = the rock of Tariq) and occupied the kingdom of the Visigoths, founding their own state in the area.

Aritmoi (numbers): Arabic numbers are used today. Until the 12th century the Byzantines used in their calculations an arithmetic range consisting of the 24 letters of the Greek alphabet plus the archaic characters, the digamma, the koppa and the sambi.

Armenian Church: The Armenians considered their Church to be the creation of St Gregory's preaching, which was conducted at the beginning of the 4th century, and the apostolic tradition of St Thaddeus. They acknowledged only the first three ecumenical councils, rejected Chalcedon and broke with the Byzantine Church. Manuel I Komnenos tried to unite the two Churches without success. From then on they turned to the Latin Church, without completely severing their ties with Byzantium.

Anastasios II (Artemios): Emperor of Byzantium (713-715 or 716). Skilled and experienced in administrative matters (before his accession to the throne he held the office of protoasekretes) he tried to increase the Empire's prestige, in particular by reinforcing the imperial army and defence.

Asen I and Peter II: Brothers and co-founders of the second Bulgarian Tsarist state as well as of its first dynasty (1186-1257).

Asparuch: Khan (ruler) of the Bulgars (680/1-701/2), founder of the First Bulgar state, with Pliska as its capital.

Aistulf: King of the Lombards(749-756).

Athanasios of Athos, St: Founder of the Great Lavra monastery in Mount Athos. He was born in Trebizond in the early 10th century and died circa 1001, on Mount Athos. Originally he was a teacher in Constantinople. In 962/3 with the help of the Emperor Nikephoros II Phokas, he founded the Lavra.

Attaleia: City and bishopric in Pamphylia (the coastal plain in the south Asia Minor), today the site of Antalya. This region had been inhabited since late antiquity. The Byzantine city that grew up in the 7th century flourished in the 9th and 11th centuries as a maritime and military centre.

automata: Mechanical constructions imitating Solomon΄s throne, singing birds and roaring lions. Moved by means of compressed air, they were demonstrated in a room of the Magnaura palace. Michael Glykas mentions that Leo the Mathematician was the mechanic responsible.

Avars: A kindred tribe of the Huns. In the middle of the 6th century they crossed southern Russia, moved west and founded a powerful state in Pannonia and the bordering Danube areas. Together with vast hosts of Slavs, the Avars conducted many raids against Byzantium. They began to disintegrate after their unsuccessful effort, in 626, to seize Constantinople with the Persians. Information on their activities after this event are sparse. Survivors of the tribe are mentioned for a last time circa 950.

axiai dia brabeion ('dignities by prizes): The honorific titles (axiai) dispensed by the emperor after a special ceremony, in which the honoured person was given an object (brabeion) symbolizing his new office. The stator for example (an ostler) was given a golden whip, whereas the spatharios was given a golden sword (spathi). These people had no real authority but were in charge of certain ceremonial activities. The spatharioi, for example, were the honorary guards of the emperor at various ceremonies.

aniconic decoration ("non-figural"): decoration based on animal, floral and geometric motives that did not allow the depiction of divine figures.

ambulatory a portico that goes round an edifice.