About Weta de Laon
From the Foundation for Medieval Genealogy page on Merovingian nobility:
"Asuarius" abbot of Prüm noted a donation to the abbey by "filia in Christo Wetane", which names "genetricis tue [Wetane] Bertradane" and "Cario et coniuge tue Wettane", by undated charter dated to [762/804].
It is not certain that "Bertradane" was the same person as the mother of Charibert, although the common connection with Prüm indicates that this is possible. If this is correct, the charter is probably datable to the earliest part of the suggested date range, assuming that the date of Bertrada's 720 charter (see above) is correct and at that date her son Charibert was already an adult.