 He was in a prime position to assassinate Dion, since most of Dion’s closest friends had been killed by Dionysius the Younger, and Callippus was his closest friend remaining.Callippus used the money from Dionysius to bribe some of Dion’s troops to defect to him.He then won Dion’s trust by betraying some of the soldiers to Dion, who then enlisted Callippus’s as a secret agent to discover further plotters.