Which fruit do raisins come from?

Grapes, dried until they hold about fifteen per cent of their original water, which is little enough that nothing can grow in them. It is one of the oldest preservation methods there is - raisins turn up in Egyptian tombs and in Roman recipes, and for most of history they were one of the very few sweet things available out of season.

The names are all the same fruit treated differently. Sultanas come from a particular seedless white grape, currants from a small dark one originally from Corinth - the name is a corruption of raisins de Corinthe and has nothing to do with the blackcurrant bush.

Grapes themselves are among the oldest domesticated crops, cultivated for at least 8,000 years, and almost every wine grape is a cutting rather than a seedling for the same reason apples are - they do not breed true. That created a catastrophic vulnerability in the nineteenth century, when an American aphid, phylloxera, reached Europe and destroyed most of the continent's vineyards within a few decades. The fix was to graft European vines onto American rootstock, which is what essentially every vine in Europe still grows on.