A slight change in format: it has been brought to my attention that my use of the OCD (namely, the frequent posting of entire articles), still under copyright, may involve a violation of the Fair Use doctrine. So instead, I’m going to use older, public-domain reference works to supply facts about antiquity chosen more or less at random. For the time being, I will use A Concise Dictionary of Greek and Roman Antiquities, by Sir William Smith and Francis Warre Cornish (John Murray, 1898). I think that I will also steal an idea of Dennis’ and from time to time compare the older entry with what we find in the OCD.
Negotiatores signified especially during the later times of the Republic Roman citizens settled in the provinces, who lent money upon interest or bought up corn on speculation (Caesar, B.G. vii. 3). Their chief business, however, was lending money upon interest as usurers; hence we find the words negotia, negotiatari, and negotiatio used in this sense. Negotiatores are distinguished from publicani (Cic. Att. ii. 16, Verr. ii. 3. 7, Leg. Manil. 7, 18), and from mercatores (Cic. Planc. 26, 64). Hence the negotiatores in the provinces corresponded to the argentarii and feneratores at Rome. The negotiatores, like the publicani, belonged to the equestrian order, but men of senatorial rank indirectly shared the gains, in return for their countenance and support. They were often accused of exacting immoderate interest from provincials; and instances of great cruelty are recorded against them.
The entry “negotiatores” in the OCD is a bit longer and provides some additional information that is helpful with respect to both terminology and the activities of such men. For instance: the term is rarely defined precisely in ancient sources. The OCD entry notes that “there were close links and involvement with the work of the publicani (tax companies), bankers, landowners, and shipping. Indeed, one rhetorical remark of Cicero’s (Font. 46) about ‘all the publicans, farmers, cattle-breeders, and the rest of the negotiatores‘ suggests that the term negotia could cover all those activities.” In general, they were simply businessman–or, better, “money-men.” They were instrumental for the “organization of markets, investment in shipping, and…credit to facilitate deals.” The term negotiator was held in higher repute than mercator, and, “while the negotiator might invest in or own ships, he did not actually sail them.”
Since, however, these figures were so closely connected to the financing of trade, by the imperial period one finds evidence that negotiator was “the normal term for trader or merchant.”
Finally, since the negotiatores were Roman citizens living in the provinces and conducting business with provincials, they were important for the process of Romanization in these areas, though the entry notes that “[t]heir overall impact on the provinces is debated.” In any case, many of these negotiatores amassed huge fortunes while in the provinces, and in the first century AD we sometimes find their descendants returning to Italy as provincial senators.