From the new town of commerce to the old town of history upon the hill, the road is carried along a rampart lined, with horse-chestnut trees—­clumps of massy foliage, and snowy pyramids of bloom, expanded in the rapture of a southern spring.  Each pair of trees between their stems and arch of intermingling leaves includes a space of plain, checkered with cloud-shadows, melting blue and green in amethystine haze.  To right and left the last spurs of the Alps descend, jutting like promontories, heaving like islands from the misty breadth below:  and here and there are towers, half-lost in airy azure; and cities dwarfed to blots; and silvery lines where rivers flow; and distant, vapour-drowned, dim crests of Apennines.  The city walls above us wave with snapdragons and iris among fig-trees sprouting from the riven stones.  There are terraces over-rioted with pergolas of vine, and houses shooting forward into balconies and balustrades, from which a Romeo might launch himself at daybreak, warned by the lark’s song.  A sudden angle in the road is turned, and we pass from airspace and freedom into the old town, beneath walls of dark brown masonry, where wild valerians light their torches of red bloom in immemorial shade.  Squalor and splendour live here side by side.  Grand Renaissance portals grinning with Satyr masks are flanked by tawdry frescoes shamming stonework, or by doorways where the withered bush hangs out a promise of bad wine.  The Cappella Colleoni is our destination, that masterpiece of the sculptor-architect’s craft, with its variegated marbles,—­rosy and white and creamy yellow and jet-black,—­in patterns, basreliefs, pilasters, statuettes, encrusted on the fanciful domed shrine.  Upon the facade are mingled, in the true Renaissance spirit of genial acceptance, motives Christian and Pagan with supreme impartiality.  Medallions of emperors and gods alternate with virtues, angels and cupids in a maze of loveliest arabesque; and round the base of the building are told two stories—­the one of Adam from his creation to his fall, the other of Hercules and his labours.  Italian craftsmen of the quattrocento were not averse to setting thus together, in one framework, the myths of our first parents and Alemena’s son:  partly perhaps because both subjects gave scope to the free treatment of the nude; but partly also, we may venture to surmise, because the heroism of Hellas counterbalanced the sin of Eden.  Here then we see how Adam and Eve were made and tempted and expelled from Paradise and set to labour, how Cain killed Abel, and Lamech slew a man to his hurt, and Isaac was offered on the mountain.  The tale of human sin and the promise of redemption are epitomised in twelve of the sixteen basreliefs.  The remaining four show Hercules wrestling with Antaeus, taming the Nemean lion, extirpating the Hydra, and bending to his will the bull of Crete.  Labour, appointed for a punishment to Adam, becomes a title to immortality for the hero.  The dignity of man