Polybius of Megalopolis (c.200 - c.118) is one of the most important historians from Antiquity. In his World History (a modern title) he describes the rise of Rome, but it contains digressions on other subjects. In the following lines, he compares the Syracusan tyrants Dionysius I and Agathocles.
The translation of World History 15.35.1-6 was made by H. J. Edward.
Polybius on the Achievements of Dionysius I and Agathocles
[15.35.1] It is not therefore advisable, as I said, to deal at excessive length with the fate of such a man,note[Polybius has just told about the death of a notorious Egyptian courtier.] but it is otherwise with the Sicilians Agathocles and Dionysius and certain other rulers of renown.
[15.35.2] Of these two, the latter started from an obscure and humble position, and Agathocles, as [the historian] Timaeus ridiculing him tells us, was a potter and leaving the wheel and the clay and the smoke came to Syracuse as a young man.
[15.35.3] In the first place they both of them became in their time tyrants of Syracuse, a city which then ranked highest in opulence and dignity,
[15.35.4] and they were afterwards recognized as kings of the whole of Sicily and had made themselves masters even of some parts of Italy.
[15.35.5] And Agathocles not only made an attempt to conquer Africa but retained his exalted position until his death
[15.35.6] So that they say that Publius Scipio,note[Publius Cornelius Scipio Africanus.] who was the first to bring Carthage to her knees, when some one asked him whom he thought the greatest statesmen combining courage and wisdom, replied "Agathocles and Dionysius the Sicilians."