Representation was codified throughout the Byzantine and Middle Ages periods and had a didactic and votive function. As a result naturalism was not the mean of representation. Giotto initiated a new way to look at religious figures. He was known to revived the style of Greek and Roman art that had been cast aside for a thousand years.
The laws of perspective were not yet defined but Giotto suggested a three dimensional world that did not exist before him in religious art.
Here in the pictures on the right, Cimabue added some perspective to the throne while Giotto expanded it by adding a gothic architecture around the Madonna. In his subsequent works Giotto will lay down some awesome three dimensional architectural backgrounds to his frescoes. To compare Giotto craft with previous artists renderings look at the frescoes of St Francis painted nine years after the death of the Saint [more on architectural rendering].