Kugler comments on the decline of Italian painting:
But the completest degeneracy is to be found in Rome, the very place in which the greatest number of the most perfect models exist. Little deserving of record was produced here up to the last thirty years of the sixteenth century; and from 1570 till 1600 every variety of manner contributed turns to reduce the Art to the very verge of ruin. Pope Gregory XIII, and his successors, erected many buildings, ordered many paintings, but rapidity of hand alone had value in their eyes; Art was degraded to the lowest mechanical labour. ( Kugler, ed. Eastlake, Handbook of the History of Painting, Part One, The Italian Schools, First Edition, p. 384)
It is unlikely, though, that Ruskin would have agreed with Kugler about what constituted the 'most perfect models'.