Discourse functions of the it-cleft
The main function of the it-cleft is to mark contrastive focus. The contrast is very often implicit, as in Tuesday (not another day), the women, not the men; but the contrast may be made explicit, as in It’s the person, not the business, who is registered for VAT.
A different, non-contrastive use, is illustrated in the following sentence from Huxley’s work:
1 It was in 1886 that the German pharmacologist, Louis Lewin, published the first systematic study of the cactus, to which his own name was subsequently given.
The function here is not to contrast 1886 with a different date. Rather, the function of such clefts, which often highlight expressions of time or place, is to signal the beginning of an episode in discourse. It may be the very beginning of the text, as in 1, or an oral announcement, 2; otherwise, the cleft may signal a shift to a new episode 3:
2 It is with great pleasure that I announce the name of this year’s winner . . .
3 It was only years later that I realized what he meant.
