The relations between Alexander and Aristotle are embittered by the execution of Aristotle's nephew, the historian Callisthenes of Olynthus, who is charged with treason.
Arrian was able to use sources which are now lost, such as the contemporary works by Callisthenes (the nephew of Alexander's tutor Aristotle), Onesicritus, Nearchus, and Aristobulus, and the slightly later work of Cleitarchus.
an identification first made by Alexander's historical advisor, Callisthenes: "the Arimoi are located by the Corycian cave near Calycadnus and the promontory of Sarpedon; the neighboring mountains are called 'Arima'".