Publius Crassus
A concept of international law, expressed in Latin by the phrase "ius gentium," existed by custom and consensus, and not in any written code or sworn treaty. By custom, the safety of hostages was guaranteed unless parties to a treaty violated its terms, in which case the subjecting of hostages to punitive actions such as torture or execution was not regarded as violating the "ius gentium". If the Armoricans believed themselves to hold the four Romans as hostages in the sense of "congestloi", it is unclear what negotiations Publius Crassus had undertaken. “Caesar liked energy and enterprise in young aristocrats,” Syme remarked, “a predilection not always attended with happy results.” Caesar reacted with military force.