As a commodity, slaves created peculiar problems for the merchant. Apparently in the larger cities there were a few shops where slaves could be bought: in Rome in Nero’s time they were concentrated near the temple of Castor in the Forum. But they were the exception. One could not keep on hand, like so much merchandise on the shelves, a supply of gladiators, pedagogues, musicians, skilled craftsmen, miners, young children, women for brothels or concubinage. The slave trade has always been conducted in a special way, and the ancient world was no exception.
On the one hand there were the main slave markets where, probably on fixed dates, dealers and agents could count on large supplies being put up for sale. Some of the centers were the obvious larger towns, such as Byzantium or Ephesus or Chios, but there were lesser markets too, like Tithorea in central Greece where there was a slave sale twice a year on the occasion of the semi-annual festival in honor of the goddess Isis. On the other hand itinerant traders went with their slaves wherever there were potential customers, to garrison towns, country fairs, and what not.
The actual sale was normally by auction. The only surviving pictorial representations are on tombstones, to be exact on two, one from Capua and the other from Arles- with substantially similar scenes. On the Arles stone the slave stands on a rotating platform while a man, presumably a possible buyer, lifts his single garment to reveal his very muscular legs and buttocks, and the auctioneer stands nearby in a characteristic pose with his arm outstretched. As the stoic philosopher Seneca observed, “When you buy a horse, you order its blanket to be removed; so, too, you pull the garments off a slave.”
ADDENDUM:
( see link at end) …When a rich man and his family bathed at home, slaves would help out by drying them once they had finished and dressing them. When a master moved around, slaves would carry him in a litter. When a master entertained, slaves would ensure a constant supply of food and drink. If guests had to return home and it was dark, a slave or slaves would walk ahead of them with a lighted torch.
The Roman writer Seneca believed that masters should treat their slaves well as a well treated slave would work better for a good master rather than just doing enough begrudgingly for someone who treated their slaves badly. Seneca did not believe that masters and their families should expect their slaves to watch them eat at a banquet when many had only had access to poor food.
“The result is that slaves who cannot talk before his (the master) face talk about him behind his back. It is this sort of treatment which makes people say, “You’ve as many enemies as you’ve slaves.” They are not our enemies when we get them; we make them so.” (Seneca) Read More:http://www.historylearningsite.co.uk/roman_slaves.htm