During this time, Alexander adopted some elements of Persian dress and customs at his court, notably the custom of proskynesis , a symbolic kissing of the hand that Persians paid to their social superiors, but a practice of which the Greeks disapproved; the Greeks regarded the gesture as the preserve of deities, and believed that Alexander meant to deify himself by requiring it. This cost him much in the sympathies of many of his Greek countrymen. Here, too, a plot against his life was revealed, and his friend Philotas was executed for treason for failing to bring the plot to his attention. Although Philotas was convicted by the assembled Macedonian army, most historians consider this one of the king's greatest crimes, along with his order to assassinate his senior general Parmenion, Philotas' father. In a drunken quarrel at Macaranda, Samarkand, he also killed the man who had saved his life at the Granicus, Clitus the Black. This is sometimes called the "murder" of Clitus, but this is a misnomer, since legally "murder" applies only to killing with premeditation, not to unpremeditated manslaughter in drunken brawls. Later in the Central Asian campaign, a second plot against his life, this one by his own pages, was revealed, and his official historian, Callisthenes of Olynthus (who had fallen out of favor with the king by leading the opposition to his attempt to introduce proskynesis ), was implicated on what most historians regard as trumped-up charges. However, the evidence is strong that Callisthenes, the teacher of the pages, must have been the one who persuaded them to assassinate the king.