Perhaps the weakest aspect of oral tradition is its inability to establish and maintain an accurate assessment of the length of the past it purports to relate. As time passes, societies without calendrical systems tend to become either very vague about this time depth or to relate it to present, changing circumstances. The most common method of measuring the past in many societies is in terms of king lists or genealogies. A comparison of orally transmitted king lists and genealogies in various places and times, for example, the early Mediterranean world and the Ancient Near East, the native states of India, Africa and Oceania, indicates that certain patterns of chronological distortion seem to emerge, sometimes telescoping but more often lengthening the past.
The former may occur through omission of usurpers, however defined, periods of chaos or foreign domination, or by the personification of an entire epoch by a founding folk-hero. If the reasons for artificial lengthening are obvious, the mechanisms are less so. In this respect a survey of both welldocumented cases and of orally transmitted lists can be instructive. Lengthening is often the result of euhemerism; more often subtler themes emerge. These include longer reigns in the earlier, less known period, the arranging of contemporary rulers as successive ones and, most importantly, extended father/son succession throughout the list or genealogy. This last is of direct and profound chronological importance, and its occurrence is widespread enough to be termed stereotypical. Yet it is not often recognized as aberrant, even though its documented occurrence is exceedingly rare. The consequent equation of reigns with generations will almost always result in an exaggerated conception of the antiquity of the beginning of the genealogy. Other weaknesses of orally transmitted king lists include lack of multiple reigns and dynastic changes, and suspiciously perfect rotational succession systems.
Within its scope this article only attempts to hint at the origin, shape and effects of these distortions. Its main thesis is that much light can be cast on African cases of this nature through a comparative analysis drawing from a whole range of societies and sources.