The Romans did not believe, as we do today, that to have a copy of an artwork was of any less value that to have the original.
Greek art certainly had a powerful influence on Roman practice; the Roman poet Horace famously said that “Greece, the captive, took her savage victor captive,” meaning that Rome (though it conquered Greece) adapted much of Greece’s cultural and artistic heritage (as well as importing many of its most famous works). It is also true that many Romans commissioned versions of famous Greek works from earlier centuries; this is why we often have marble versions of lost Greek bronzes such as the Doryphoros by Polykleitos.
The Romans did not believe, as we do today, that to have a copy of an artwork was of any less value that to have the original. The copies, however, were more often variations rather than direct copies, and they had small changes made to them. The variations could be made with humor, taking the serious and somber element of Greek art and turning it on its head.
So, for example, a famously gruesome Hellenistic sculpture of the satyr Marsyas being flayed was converted in a Roman dining room to a knife handle. A knife was the very element that would have been used to flay the poor satyr, demonstrating not only the owner’s knowledge of Greek mythology and important statuary, but also a dark sense of humor. From the direct reporting of the Greeks to the utilitarian and humorous luxury item of a Roman enthusiast, Marsyas made quite the journey.
But the Roman artist was not simply copying. He was also adapting in a conscious and brilliant way. It is precisely this ability to adapt, convert, combine elements and add a touch of humor that makes Roman art Roman.