That is the impression they make, and it predicates a singular power of imagination.

Like the Prometheus of Goethe, the poet sits apart, moulding men and then endowing them with life.

But he cannot tell, any more than Prometheus, what they will say and do after he has made them.

He does tell, of course, but that is not our impression.

Our impression is that they live and talk of their own accord, so vitally at home they are in the country, the scenery, and the thinking of the place and time in which he has imagined them.
Great knowledge seems required for this, and Browning had indeed an extensive knowledge not so much of the historical facts, as of the tendencies of thought which worked in the times wherein he placed his men.