Arrian of Nicomedia was a Greek historian, public servant, military commander, and philosopher of the Roman period.

The Anabasis of Alexander was composed by Arrian of Nicomedia in the second century AD, most probably during the reign of Hadrian. The Anabasis is a history of the campaigns of Alexander the Great, specifically his conquest of the Persian Empire between 336 and 323 BC. Both the unusual title "Anabasis" and the work's seven-book structure reflect Arrian's emulation of the Greek historian Xenophon, whose own Anabasis in seven books concerned the earlier campaign "up-country" of Cyrus the Younger in 401 BC.