some precursors of Mantegna

Light. And shade. Line and shape. Colour, form and perspective. Wall, wood, ceiling or canvas. Pigment in eggyolk or linseed oil. Stroked by brush or spread by knife. On small panels or plastered on vast spaces. All these problems to be worked over and solved. Then a commission from the Medici or the Roman Pope. Unless you happen to work in Flanders in an artists' guild. There to use van Eyck's oil on wood for more humble means. To observe a real scene and not a cupid floating on a cloud. But back in Florence circa 1434 wedding portraits are not exactly where it's at. There the Medici have dispensed their bankers' ducats to Donatello for David, his bronze nude. Brunellischi has been busy building mighty chapels, naturally, for man builds a city, banks and cathedral. To get inside you go through doors of Paradise designed by Ghiberti with panels of gilded bronze. In this city of churches many splendours of frescoe and painted panel adorn the walls and altarpieces therein. Commissioned by the wealthy and powerful they depict scenes of religious symbolism dedicated to the glory of almighty god. The lord and his angels are still wearing halos and there is not a cupid to be seen amongst them. In one panel base humanity is seen stepping impossibly out of a narrow alcove, its nakedness exposed, heading blindly towards some future art. Perhaps it is trekking into another frame altogether, of some as yet unimagined realism, perhaps to reassemble as Neptune and Amphitrite. In the meantime it will be more decorous to be strapped to a post while philosophers dressed in rich cloaks discuss its fate. Where for perspective there are grid lines on the floor and Greek columns framing a pale blue sky, beneath which shadows are strangely missing. The theories of Alberti don't seem to be working, and the procession winding down from the hill cannot quite manage to step out of the wall. Trancelike, the madonna will seem forever separated from her child and her angels by a thin line, no matter how skilful deemed by later learned scholars. There are tricks of the art to be mastered yet before in time these years five hundred hence where outside the ghost of raphael comes and goes.  And where inside below the  Sistine ceiling  as they quaff spumante beneath the sfumato that the great Michelangelo plastered the Cardinals are reeling from their wheeling and dealing.     And where  speaking of Michelangelo the critics are comparing him to Picasso ever since the theorists concluded no illusions are impossible now that all the tricks have been mastered.