As the principal sources of Arrian, Ptolemy and Aristobulus occupy a privileged position in the historiographical tradition on Alexander, although their histories survive only in fragments. Both wrote eyewitness accounts of Alexander’s expedition, and offer valuable insight as to how Alexander spun some of the more controversial aspects to his contemporaries. Ptolemy was a high-ranking officer, and so his history focused on the military events, in which he exaggerated his own contributions in order to portray himself as a worthy successor to Alexander. He also emphasized his close association with Alexander (reconfigured as a Ptolemaic predecessor) in order to legitimate the foundation of his future dynasty in Egypt. Aristobulus’ role on the expedition, on the other hand, appears not to have been a military one. His generally eulogistic treatment of Alexander focuses upon his clemency, although occasionally overt criticisms of his ruthless imperialism and increasing megalomania can be discerned. Because Aristobulus is largely unknown apart from the authorship of his history, it is difficult to ascertain in whose interest he manipulated the figure of Alexander, whose memory had become hotly contested in the turbulent years after his premature death.

Alexander III inherited the Persian campaign from his father Philip II, who had aimed to conquer Asia Minor, probably in order to secure a permanent source of income from the revenues of its rich cities. Going further, Alexander ended the reign of the Achaemenid dynasty established by Darius I in 522/21 BC and campaigned to the borders of Achaemenid influence in the Indus region. Contrary to the panhellenic propaganda preserved by the Alexander historiographers, the war was about the acquisition of territory, influence and wealth – not a war of ‘liberation’ or ‘reprisal’. Since there exists no Persian historiography and the extant numismatic, administrative and archaeological sources reveal little of political history, it is difficult to view the events from a Persian perspective. However, scholarship’s traditional biased images of the Persian empire as weak, chaotic, compromised by decadence and inner strife, and hence doomed to fall, have come to be rejected as reflecting Greek and Roman stereotypes. In current scholarship, it is stressed that Alexander appropriated and adapted most of the political and administrative structures of the Achaemenid empire: it was the existing system that supported his conquest.