Lucius Flavius Arrianus (c.87 - after 145), Greek philosopher and historian.
He is commonly known as Arrian. His best-known work is the Anabasis Alexandri, about Alexander the Great. He was a lifelong friend of the emperor Hadrian. Though a man of considerable wealth, besides his writings he pursued a senatorial career which culminated in his governorship of Cappadocia. He retired to Athens and held the archonship in 145/146, listed under the name of Flavius Arrianus Paianieus. He may have survived into the reign of Marcus Aurelius.
Most of his writings, which include lecture transcriptions of the philosopher Epictetus, are no longer extant. For a complete list, scroll down in the above link. (at livius.org)
The bottom of the Wikipedia page lists other available online texts.
Anabasis (Greek) means expedition from a coastline into the interior of a country. (corrected from original post). Xenophon wrote Anabasis Kyrou, the expedition of Cyrus.