What a fact of music history is seems to need no explanation. Works of music and performances of them, the matters surrounding the lives of the composers who wrote them, the structures of the institutions for which they were intended, even the aesthetic ideas of the age and the social strata that sustain musical genres – none of these has ever been denied a place among the facts which go to make up a piece of music history. Nor do music historians feel specially upset to learn that the range of facts in music history is by nature boundless. It obviously depends on how the question is formulated as to whether any given state of affairs forms, or does not form, a fact of music history, one that figures in the picture of music history given in the preceding chapter. However this may be, the assurance that works, composers, institutions and ideas at all events form a central core of the facts of music history offers a firm support, even in the face of open boundaries.

Yet even the most casual attempt to learn how musical and music-historical facts are related and in what sense a musical fact can be regarded at all as an historical one leads us quickly along tortuous byways, and the difficulties that entangle us are by no means simply phantoms conjured up by unnecessary and, for the historian, irrelevant speculations.