Barbara Yorke wrote: "Although it is possible that some kind of regnal list could be the source of the information (though the Worcester lists begin with Penda), these entries could be nothing more than intelligent guesswork based on names derived from Bede and the genealogy of Æthelred, while the dates seem to be influenced by an entry in the Anglo-Saxon Chronicle for the death of a West Saxon Creoda...The surviving sources allow us to say with confidence little more than that the kingdom of Mercia was in existence by the end of the sixth century.

"[3] Yorke's sentiment is shared by Professor of Medieval History Nicholas Brooks, who wrote: "Despite Professor Davies's tentative advocacy of the historicity of this material, it cannot be said that it is yet clear that what lies behind these scattered entries in the works of Henry of Huntingdon, Roger of Wendover and Matthew Paris is anything more important than some inventive conjectures by an English monk, perhaps as late as the early twelfth century, on the basis of the names available in Bede, the Mercian royal genealogy and the Anglo-Saxon Chronicle.

On such an interpretation it would not be surprising that they should more or less fit the fragments of information that we have on the early history of Mercia; for the compiler of these entries may have had access to the same sources as are available to us.

"[4] The suggestion that Creoda was a king of Mercia is to be found in the Historia Anglorum, which was written by Henry of Huntingdon in the first half of the 12th century.

[2] Creoda is recorded by the Mercian pedigree in the Anglian collection as having been the son of Cynewald and the great-grandson of Icel, the eponymous ancestor of his family, the Iclingas.