Jameson writes in her Guide to the Public Galleries (1842):
There is a moral and poetical grandeur in Salvator's scenes which in my mind places him as a landscape painter above Rubens. ( Jameson, Hand-book to the Public Galleries of Art in and near London, p. 27)
For Kugler, ed. Eastlake, Handbook of the History of Painting, Part One, The Italian Schools, First Edition ( Murray's Handbook of Painting in Italy):
He displays more beauty and originality in wild mountain scenes, lonely defiles and deep forests; but most of all in landscapes of smaller dimensions, where this fantastic conception of nature is more concentrated and the whole seems to express, as it were, a single chord, a hint for the mind, a momentary feeling rather than the complete expression of a comprehensive idea. In these he usually introduces hermits, robbers or wandering soldiers, who assist the general effect of the picture and add to the impression of loneliness, desolation and fear.
In 1846 Head, in a footnote to his edition of Kugler's Handbook on the German, Flemish and Dutch Schools, quotes a passage from Schlegel discussing the influence of the landscape with which painters were familiar in their youth. Both Head and Schlegel take it for granted that Rosa was the 'greatest painter of wild and savage scenes'. ( Kugler, edited Head, Handbook of Painting: German, Flemish and Dutch Schools, First Edition, p. 308n)