[MerManMaid]

>History is written by the winners. 100% of that "he led the flank himself and commanded while the other men just watched" is suspect.

History is written by the literate. (i.e. the rich for most of human history)

In this case, most information about Alexander the Great comes from four distinct sources, the most famous being Arrian of Nicomedia who famously used Ptolemy I Soter as their primary source.

Ptolemy at the time he wrote his testimony was already a king and only had benefit of grandizing his own contributions not his old King. His account was famed for how straightforward it was and seemed only to confirm Alexander's exceptional leadership in battle.