Natale Barca's study sets the revolts of Ennius and Salvius in their social context, describing the nature of slavery in the Late Republic and while explaining the causes behind the revolt.

In 136 BC, in Sicily (which was then a Roman province), some four hundred slaves of Syrian origin rebelled against their masters and seized the city of Henna with much bloodshed. Their leader, a fortune-teller named Eunus, was declared king (taking the Syrian royal name Antiochus), and tens of thousands of runaway slaves as well as poor native Sicilians soon flocked to join his fledgling kingdom. Antiochus' ambition was to drive the Romans from the whole of Sicily. The Romans responded with characteristic intransigence and relentlessness, leading to years of brutal warfare and suppression. Antiochus' 'Kingdom of the Western Syrians' was extinguished by 132 but his agenda was revived in 105 BC when rebelling slaves proclaimed Salvius as King Tryphon, with similarly bitter and bloody results.

Natale Barca narrates and analyses these events in unprecedented detail, with thorough research into the surviving ancient sources. The author also reveals the long-term legacy of the slaves' defiance, contributing to the crises that led to the seismic Social War and setting a precedent for the more-famous rebellion of Spartacus in 73-71 BC.