passage: During this time , Alexander adopted some elements of Persian dress and customs at his court , notably the custom of proskynesis , either a symbolic kissing of the hand , or prostration on the ground , that Persians showed to their social superiors .
  The Greeks regarded the gesture as the province of deities and believed that Alexander meant to deify himself by requiring it .
  This cost him the sympathies of many of his countrymen , and he eventually abandoned it .
  A plot against his life was revealed , and one of his officers , Philotas , was executed for failing to alert Alexander .
  The death of the son necessitated the death of the father , and thus Parmenion , who had been charged with guarding the treasury at Ecbatana , was assassinated at Alexander 's command , to prevent attempts at vengeance .
  Most infamously , Alexander personally killed the man who had saved his life at Granicus , Cleitus the Black , during a violent drunken altercation at Maracanda ( modern day Samarkand in Uzbekistan ) , in which Cleitus accused Alexander of several judgemental mistakes and most especially , of having forgotten the Macedonian ways in favour of a corrupt oriental lifestyle .
  Later , in the Central Asian campaign , a second plot against his life was revealed , this one instigated by his own royal pages .
  His official historian , Callisthenes of Olynthus , was implicated in the plot ; however , historians have yet to reach a consensus regarding this involvement .
  Callisthenes had fallen out of favor by leading the opposition to the attempt to introduce proskynesis .
query_and_answer: Why do historians disagree about Callistheness ? || Historians disagree about whether or not Callisthenes was involved in the plot against Alexander's life in the Central Asia campaign
evidences: His official historian , Callisthenes of Olynthus , was implicated in the plot ; however , historians have yet to reach a consensus regarding this involvement . Callisthenes had fallen out of favor by leading the opposition to the attempt to introduce proskynesis .