The author examines the evidence of Diodorus’ Biblotheca Historica concerning the political situation in South Italy in the early 4th century BC. One of the most important persons in this narrative is Heloris, who was the adoptive father of Dionysios the Elder. The main source on the activity of this person seems to be Philistus’ book Περὶ Διονυσίου. The historian tried to represent Heloris as an enemy of the Syracusan tyrant and the creator of the Italiote League. It seems that Philistus, describing the character of the league from the military point of view only, missed other features of the Italiote political unity.