Terence as a rule does not base his play upon a single Greek original, but levies contributions from two or more, and exercises his talent in harmonising the different elements. This process is known as _contamination_; a word that first occurs in the prologue to the _Andria_, and indicates an important and useful principle in imitative dramatic literature. The ground for this innovation is given by W. Wagner as the need felt by a Roman audience for a quick succession of action, and their impatience of those subtle dialogues which the Greeks had so much admired, and which in most Greek plays occupy a somewhat disproportionate length. The dramas in which "contamination" is most successfully used are, the _Eunuchus_, _Andria_, and _Adelphoe_; the last-mentioned being the only instance in which the two models are by different authors, viz. the _Adelphoi_ of Menander and the _Synapothnaeskontes_ of Diphilus. So far as the metre and language went, Terence seems to have followed the Greek much more closely than Plautus, as was to be expected from his smaller inventive power. Quintilian, in commending him, expresses a wish that he had confined himself to the trimeter iambic rhythm. To us this criticism is somewhat obscure. Did the Romans require a more forcible style when the long iambic or the trochaic was employed? or is it the weakness of his metrical treatment that Quintilian complains of? Certainly the trochaics of Terence are less clearly marked in their rhythm than those of Ennius or Plautus.