It is only necessary to contrast the two finest cathedrals of this style, those of Siena and Orvieto, with two such buildings as the cathedrals of Rheims and Salisbury, in order to perceive the structural inferiority of the former, as well as their superiority for all subordinate artistic purposes.  Long straight lines, low roofs, narrow windows, a facade of surprising splendour but without a strict relation to the structure of the nave and aisles, a cupola surmounting the intersection of nave, choir, and transepts; simple tribunes at the east end, a detached campanile, round columns instead of clustered piers, a mixture of semicircular and pointed arches; these are some of the most salient features of the Sienese Duomo.  But the material is all magnificent; and the hand, obedient to the dictates of an artist’s brain, has made itself felt on every square foot of the building.  Alternate courses of white and black marble, cornices loaded with grave or animated portraits of the Popes, sculptured shrines, altars, pulpits, reliquaries, fonts and holy-water vases, panels of inlaid wood and pictured pavements, bronze candelabra and wrought-iron screens, gilding and colour and precious work of agate and lapis lazuli—­the masterpieces of men famous each in his own line—­delight the eye in all directions.  The whole church is a miracle of richness, a radiant and glowing triumph of inventive genius, the product of a hundred master-craftsmen toiling through successive centuries to do their best.  All its countless details are so harmonised by the controlling taste, so brought together piece by piece in obedience to artistic instinct, that the total effect is ravishingly beautiful.  Yet it is clear that no one paramount idea, determining and organising all these marvels, existed in the mind of the first architect.  In true Gothic work the details that make up the charm of this cathedral would have been subordinated to one architectonic thought; they would not have been suffered to assert their individuality, or to contribute, except as servants, to the whole effect.  The northern Gothic church is like a body with several members; the southern Gothic church is an accretion of beautiful atoms.  The northern Gothic style corresponds to the national unity of federalised races, organised by a social hierarchy of mutually dependent classes.  In the southern Gothic style we find a mirror of political diversity, independent personality, burgher-like equality, despotic will.  Thus the specific qualities of Italy on her emergence from the Middle Ages may be traced by no undue exercise of the fancy in her monuments.  They are emphatically the creation of citizens—­of men, to use Giannotti’s phrase, distinguished by alternating obedience and command, not ranked beneath a monarchy, but capable themselves of sovereign power.[14]