Quintus Curtius Rufus
Several much later Greek and Roman accounts (including Arrian, Diodorus Siculus and Quintus Curtius Rufus) describe that the burning was the idea of Thaïs, mistress of Alexander's general Ptolemy I Soter, and possibly of Alexander himself. She is said to have suggested it during a very drunken celebration, according to some accounts to revenge the destruction of Greek sanctuaries (she was from Athens), and either she or Alexander himself set the fire going.