The first of these, of course, is the Assumption of the Madonna, of which Caccia says there was a representation of her "Come ascese in Cielo, con le statue delli dodeci Apostoli intorno di rilievo," and there may very well have been a benefactor or so in addition.
"Ex Voto"
Samuel Butler
Of Donatello as an innovator I have said something above, in considering the Florentine Davids, but he was also the inventor of that low relief in which his school worked, called rilievo stiacciato, of which there are some excellent examples at South Kensington.
"A Wanderer in Florence"
E. V. Lucas
Thinking that perhaps the girl was praying, the warden's wife waited some minutes, but no sound greeted her; and so motionless was the figure, that it might have been only an alto rilievo carved on the wall.
"At the Mercy of Tiberius"
August Evans Wilson