There was one particular thing in Venice that I wanted to see, and so indeed did Jill. Again, reverting to Johannes Wilde, that best of all teachers, he had spoken of Titian’s Assunta, which is a great altarpiece, arch-topped, of the assumption of the blessed Virgin Mary, and had said that no one should ever go to Venice without seeing this picture, not only in the morning, but in the late afternoon. Because it’s in the apse of a Gothic church with high Gothic windows, and the light comes in from one side, and then it comes in from the other side. And the light is an entirely different colour in the afternoon.

And I thought that encapsulates a lesson, a great lesson: that you should never make up your mind about any painting, or any building, for that matter, on seeing it once at one time of day, that one should always go back and see how it feels, or get up very early in the morning and see what it’s like in the cold dawn light.

And again, Jill and I swanned off to see it, well, rather more than twice, because it changed. It was an extraordinary picture. It changed from morning to afternoon.

And having picked up that hint, you then apply it elsewhere, and particularly to architecture, it’s hugely important, because the shadows get thrown in a completely contrary direction, and the thing does not look the same.