Except for some extreme metaphrasers in the early Christian period and the Middle Ages, and adapters in various periods (especially pre-Classical Rome, and the 18th century), translators have generally shown prudent flexibility in seeking equivalents—"literal" where possible, paraphrastic where necessary—for the original meaning and other crucial "values" (e.g., style, verse form, concordance with musical accompaniment or, in films, with speech articulatory movements) as determined from context.
In general, translators have sought to preserve the context itself by reproducing the original order of sememes, and hence word order—when necessary, reinterpreting the actual grammatical structure, for example, by shifting from active to passive voice, or vice versa.
The translator's role as a bridge for "carrying across" values between cultures has been discussed at least since Terence, the 2nd-century-BCE Roman adapter of Greek comedies.
The translator's role is, however, by no means a passive, mechanical one, and so has also been compared to that of an artist.
The main ground seems to be the concept of parallel creation found in critics such as Cicero.