We first conceived of this study several years ago, when our respective lines of research seemed to some extent to converge on the period of the decline of ancient Ghana. It has proved a more complex matter than we imagined, or than the deceptively simple title above might suggest--partly because it is often more difficult to prove that something did not happen than that it did. We have had to divide our analysis into two parts. First we examine the external written sources for the Almoravid conquest of Ghana. Our work in this respect has been immensely facilitated by the appearance in 1975 of Cuoq's Recueil des sources arabes, which in some sense provides the infrastructure for our argument. We have also had the invaluable privilege of seeing in proof Hopkins' and Levtzion's Corpus of early Arabic sources. In the second half of our study, it will be the turn of internal sources, mainly oral traditions. We use the terms external and internal advisedly, since the simple distinction between written sources and oral traditions is too artificial: an oral tradition was an oral tradition, whether written down in Arabic in the Middle Ages or in French in this century, and a great deal of the information in both parts of our article must have started as oral tradition.Putting it very bluntly, we have discovered no sources, whether external or internal, which unambiguously point to such a conquest. A handful of sources suggest some link between the rise of the Almoravids and the decline of Ghana, but with a puzzling vagueness--a vagueness which decreases as the number of centuries between the alleged event, and the report of it increases.