Cader Idris, by Richard Wilson. Exhibited around 1774.

Richard Humphreys/David Dimbleby:

RH: 'Wilson, of course, is famous perhaps above all for having gone to Rome and painted the landscape there and brought back a taste for that kind of landscape and spread this interest in the classical Roman landscape among the aristocracy. But of course he was from Wales and what he really did was to go to Wales and reinvent Wales in the image of the Roman campagna you know with the landscape in that part of Italy. Although in fact in the case of Cader Idris, the images we're looking at, he's clearly very interested in the precise topography of what he's looking at. Cader Idris is this peak in Snowdonia. You can see the lake there and you also see the figures in the foreground and a man sketching and someone looking through a telescope out to the Cardigan Bay. So he's obviously actually very interested in the fact that it's a very particular place in Wales with certain mythological overtones and of course that would have been what people would want and that's what you would have had in a classical Roman landscape, And in this case the mythical overtones are Arthurian - this is a kind of giant seat, it's also sometimes called Arthur's Seat - and so it has a lot of local mythological and folkloric significance as well. '

DD: 'So how long did British landscape painters derive their vision from classical painting in France or Italy and impose that on the British landscape'

RH: 'I would say until the early 19th century you found people wanting a classical landscape format and that was part of the reason for instance why Constable had trouble. And it wasn't really until the mid-19th century that that whole taste had disappeared and people were genuinely interested in actual places viewed more realistically.'