The main landscape of Sordello is the plain and the low pine-clad hills around Mantua; the half-circle of the deep lagoon which enarms the battlemented town; and the river Mincio, seen by Sordello when he comes out of the forest on the hill, as it enters and leaves the lagoon, and winds, a silver ribbon, through the plain.  It is the landscape Vergil must have loved.  A long bridge of more than a hundred arches, with towers of defence, crosses the marsh from the towered gateway of the walls to the mainland, and in the midst of the lagoon the deep river flows fresh and clear with a steady swiftness.  Scarcely anywhere in North Italy is the upper sky more pure at dawn and even, and there is no view now so mystic in its desolation.  Over the lagoon, and puffing from it, the mists, daily encrimsoned by sunrise and sunset, continually rise and disperse.

The character and the peculiarities of this landscape Browning has seized and enshrined in verse.  But his descriptions are so arranged as to reflect certain moments of crisis in the soul of Sordello.  He does not describe this striking landscape for its own sake, but for the sake of his human subject.  The lines I quote below describe noon-day on the lagoon, seen from the golden woods and black pines; and the vision of the plain, city and river, suddenly opening out from the wood, symbolises the soul of Sordello opening out from solitude “into the veritable business of mankind.”

                Then wide
    Opened the great morass, shot every side
    With flashing water through and through; a-shine,
    Thick-steaming, all-alive.  Whose shape divine
    Quivered i’ the farthest rainbow-vapour, glanced
    Athwart the flying herons?  He advanced,
    But warily; though Mincio leaped no more,
    Each footfall burst up in the marish-floor
    A diamond jet.

And then he somewhat spoils this excellent thing by a piece of detail too minute for the largeness of the impression.  But how clear and how full of true sentiment it is; and how the image of Palma rainbowed in the mist, and of Sordello seeing her, fills the landscape with youthful passion!

Here is the same view in the morning, when Mincio has come down in flood and filled the marsh: 

                Mincio, in its place,
    Laughed, a broad water, in next morning’s face,
    And, where the mists broke up immense and white
    I’ the steady wind, burned like a spilth of light
    Out of the crashing of a million stars.

It were well to compare that brilliant piece of light with the grey water-sunset at Ferrara in the beginning of Book VI.

                While eve slow sank
    Down the near terrace to the farther bank,
    And only one spot left from out the night
    Glimmered upon the river opposite—­
    breadth of watery heaven like a bay,
    A sky-like space of water, ray for ray,
    And star for star, one richness where they mixed
    As this and that wing of an angel, fixed,
    Tumultuary splendours folded in
    To die.