The earlier period, about which the information contained in the sources appears semi-mythical, has not been attempted.
The reconstruction is based mainly on information extracted from Irish annals, in particular the Annals of Tigernath and Ulster (discussed in more detail in the Introduction to the document IRELAND), and in the 10th to 14th century Scottish chronicles which were collected by Skene in 1867 are two other important sources which have been consulted, although the former is unreliable on many points of detail.
It is of course not known which earlier sources, since disappeared, may have been used in the compilation of the later manuscripts.
Nevertheless, this phenomenon of expanded information over time does not inspire confidence in the overall reliability of the data.
As will be observed when studying this document, these different primary sources are mutually contradictory in many areas.
The major point of difference concerns the regnal years, which means that dating of the early Scottish kings is reliable only when it can be checked against outside sources such as the Anglo-Saxon Chronicle.The early history of Scotland is characterised by the absence of contemporary Scottish sources before the 10th century.This contrasts markedly with the situation in nearly all other European countries during the same period.Reliable information now available about the early Scottish kingdom and its kings is therefore limited.The present document attempts to reconstruct the genealogy of the Scottish kings from the mid-9th century.No Scottish chronicles survive for this period and references to Scottish affairs in English chronicles are infrequent, although more information is included in Irish chronicles.In addition, the earliest confirmed Scottish royal charter dates from the reign of King Duncan II at the end of the 11th century, in contrast to the comparative wealth of charter evidence which has survived for Anglo-Saxon England.In this context, one is reminded of the lengthy genealogies included in the later Anglo-Saxon chronicles which, as discussed in the Introduction to the document ANGLO-SAXON KINGS, were probably designed to reinforce the legitimacy of usurping monarchs and are of dubious factual accuracy.An interesting case from the Scottish documentation appears to support this hypothesis: that of King Eochlaid, whose reign is dated to the 880s.However, when we read the 11th century Synchronisms of Flann Mainistreach, we see that the information has been expanded to show all the kings as related to each other.In the case of Kings Aedh and Indulf, they are stated to have been, respectively, the brother of King Constantine I and the son of King Constantine II.