Arrian of Nicomedia (ˈæriən; Greek: Ἀρριανός Arrianos; Lucius Flavius Arrianus; 86/89-after 146/160 AD) was a Greek historian, public servant, military commander, and philosopher of the Roman period.
The Anabasis of Alexander by Arrian is considered the best source on the campaigns of Alexander the Great. Scholars have generally preferred Arrian to other extant primary sources, though this attitude has changed somewhat in light of modern studies into Arrian's method.
Arrian was born in Nicomedia (present-day İzmit), the provincial capital of Bithynia. Cassius Dio called him Flavius Arrianus Nicomediensis. Sources provide similar dates for his birth, within a few years prior to 90, 89, and 85–90 AD. The line of reasoning for dates belonging to 85–90 AD is because of Arrian being made a consul around 130 AD, and the usual age for this, during this period, being 42 years of age. (ref. pp. 312, & SYME 1958, ibid.). His family was from the Greek provincial aristocracy, and his full name, L. Flavius Arrianus, indicates that he was a Roman citizen, suggesting that the citizenship went back several generations, probably to the time of the Roman conquest some 170 years before.
Sometime during the second century AD (117 to 120 AD) while in Epirus, probably Nicopolis, Arrian attended lectures of Epictetus of Nicopolis, and proceeded within a time to fall into his pupillage, a fact attested to by Lucian. All that is known about the life of Epictetus is due to Arrian, in that Arrian left an Encheiridion (Handbook) of Epictetus' philosophy. After Epirus, he went to Athens, and while there, he became known as the "young Xenophon" as a consequence of the similarity of his relationship to Epictetus as Xenophon had to Socrates.
For a period, some time about 126 AD, he was a friend of the emperor Hadrian's, who appointed him to the Senate. He was appointed to the position consul suffectus around 130 AD, and then, in 132 AD (although Howatson shows 131), he was made prefect or legate (governor) of Cappadocia by Hadrian, a service he continued for six years.