A note on terminological usage. Throughout the series, the terms "Roman" and "Greek" are used in a way which is perhaps confusing to readers who are not very familiar with the historical setting. So a brief explanation may be helpful.
By the sixth century a.d., the only part of the Roman Empire still in existence was what is usually called by modern historians the Eastern Roman Empire, whose capital was in Constantinople. The western lands in which the Roman Empire originated—including Rome itself and all of Italy—had long since fallen under the control of barbarian tribes like the Ostrogoths.
The so-called "eastern" Roman Empire, however, never applied that name to itself. It considered itself—and did so until its final destruction at the hands of the Ottoman Turks in 1453 a.d.—as the Roman Empire. And thus, when referring to themselves in a political sense, they continued to call themselves "Romans."
Ethnically speaking, of course, there was very little Latin or Roman presence left in the Roman Empire. In terms of what you might call its "social" content, the Roman Empire had become a Greek empire in all but name. In Justinian's day, Latin was still the official language of the Roman Empire, but it would not be long before Greek became, even in imperial decrees and political documents, the formal as well as de facto language of the Empire. Hence the frequency with which the same people, throughout the course of the series, might be referred to (depending on the context) as either "Roman" or "Greek."
Loosely, in short, the term "Roman" is a political term; the term "Greek" a social, ethnic or linguistic one—and that is how the terms are used in the series.
Adulis: a city on the western coast of the Red Sea; the kingdom of Axum's major port; later, the capital city of the Ethiopians.
Ajmer: the major city of Rajputana.
Alexandria: the major city of Roman Egypt, located on one of the mouths of the Nile.
Amaravati: the former capital of the Empire of Andhra, located on the Krishna river in south India; sacked by the Malwa; Shakuntala taken into captivity after her family is massacred.
Anatha: an imperial villa in Mesopotamia; site of the first major battle between Belisarius and the Malwa.
Axum: the name refers both to the capital city in the highlands and the kingdom of the Ethiopians.
Babylon: ancient city in Mesopotamia, located on the Euphrates; site of a major siege of the Persians by the Malwa.
Barbaricum: the major port in the Indus delta; located near present day Karachi.
Begram: the major city of the Kushans.
Bharakuccha: the major port of western India under Malwa control; located at the mouth of the Narmada river.
Charax: Persian seaport on the Persian Gulf.
Chowpatty: Malwa naval base on the west coast of India; located at the site of present day Mumbai (Bombay).
Constantinople: capital of the Roman Empire; located on the Bosporus.
Ctesiphon: capital of the Persian empire; located on the Tigris river in Mesopotamia.
Deccan: southern India.
Deogiri: a fortified city in central Majarashtra; established by Shakuntala as the new capital of Andhra.
Gwalior: location of Venandakatra's palace in north India where Shakuntala was held captive.
Hindu Kush: the mountains northwest of the Punjab. Site of the Khyber Pass.
Kausambi: capital of the Malwa empire; located in north India, at the junction of the Ganges and Jamuna rivers.
Majarashtra: literally, "the Great Country." Land of the Marathas, one of India's major nationalities.
Marv: an oasis city in Central Asia; located in present day Turkmenistan.
Mindouos: a battlefield in Mesopotamia where Belisarius fought the Persians.
Muziris: the major port of the kingdom of Kerala in southeastern India.
Nehar Malka: the ancient canal connecting the Euphrates and Tigris rivers; scene of a battle between Belisarius and the Malwa.
The Pass: a pass in the Zagros mountains separating Mesopotamia from the Persian plateau; site of a battle between Belisarius and Damodara; called The Battle of the Mongoose by the Rajputs.
Peshawar: located in the Vale of Peshawar, between the Punjab and the Khyber Pass.
Punjab: the upper Indus river valley.
Rajputana: the land of the Rajputs, one of India's major nationalities.
Sind: the lower Indus river valley.
Sukkur: a major city on the Indus; north of the city is the "Sukkur gorge" which marks the boundary between Sind and the Punjab.
Suppara: a port city on India's west coast, to the north of Chowpatty.
Tamraparni: the island of Ceylon; modern day Sri Lanka.
Vindhyas: the mountain range which marks the traditional boundary between northern India and southern India.
Anvaya-prapta sachivya: members of the Malwa royal clan.
Aqabe tsentsen: literally, "keeper of the fly-whisks." The highest ranked official in the Axumite government.
Azadan: literally, "men of noble birth." Refers to a class of people in the Persian empire roughly analogous to medieval European knights.
Cataphract: the heavily armed and armored mounted archer and lancer who formed the heart of the Roman army. Developed by the Romans as a copy of the dehgan.
Dawazz: a slave assigned as adviser to Ethiopian princes, specifically for the purpose of deflating royal self-aggrandizement.
Dehgan: the Persian equivalent of a cataphract.
Dromon: a Roman war galley.
Kushans: originating as a barbarian tribe from the steppes, the Kushans became civilized after conquering Central Asia and were the principal support for Buddhism in the early centuries of the Christian Era; later subjugated by the Malwa.
Negusa nagast: "King of Kings." Ruler of Axum, the kingdom of the Ethiopians.
Nika: the name of the insurrection against Justinian and Theodora engineered by the Malwa.
Peshwa: roughly translates as "vizier." Top civilian official of the Empire of Andhra.
Sahrdaran: the highest ranked nobility in the Persian empire, next in status to the emperor. Traditionally consisted of seven families, of which the "first among equals" were the Suren.
Sarwe: a regiment of the Axumite army. The plural is "sarawit." Individual soldiers are called "sarwen."
Spatha: the standard sword used by Roman soldiers; similar to the ancient Roman short sword called the gladius, except the blade is six inches longer.
Vurzurgan: "grandees" of the Persian empire. Noblemen ranked between the azadan and the sahrdaran.
Ye-tai: a barbarian tribe from central Asia incorporated into the Malwa governing structure. Also known as "Ephthalites" or "White Huns."