The Anabasis is by far the fullest surviving account of Alexander's conquest of the Persian empire. It is primarily a military history, reflecting the content of Arrian's model, Xenophon's Anabasis; the work begins with Alexander's accession to the Macedonian throne in 336 BC, and has nothing to say about Alexander's early life (in contrast, say, to Plutarch's Life of Alexander). Nor does Arrian aim to provide a complete history of the Greek-speaking world during Alexander's reign. Arrian's chief sources in writing the Anabasis were the lost contemporary histories of the campaign by Ptolemy and Aristobulus and, for his later books, Nearchus. One of Arrian's main aims in writing his history seems to have been to correct the standard "Vulgate" narrative of Alexander's reign that was current in his own day, primarily associated with the lost writings of the historian Cleitarchus.