Book excerpt: Dante Alighieri (1265-1321) is one of the greatest European writers, whose untrammelled imaginative capacity was matched by a huge base in embracing the science of his era. His texts also paint compelling visual images. In Visions of Heaven, renowned scholar Martin Kemp investigates Dante's supreme vision of divine light and its implications for the visual artists who were the inheritors of Dante's vision. The whole book may be regarded as a new Paragone (comparison), the debate that began in the Renaissance about which of the arts is superior. Dante's ravishing accounts of divine light set painters the severest challenge, which took them centuries to meet. A major theme running through Dante's Divine Comedy, particularly in its third book, the Paradiso, centres on Dante's acts of seeing (conducted according to optical rules with respect to the kind of visual experience that can be accomplished on earth) and the overwhelming of Dante's earthly senses by heavenly light, which does not obey his rules of earthly optics. The repeated blinding of Dante by excessive light sets the tone for artists' portrayal of unseeable brightness.