The extreme length of Æthelberht's reign also has been regarded with skepticism by historians; it has been suggested that he died in the fifty-sixth year of his life, rather than the fifty-sixth year of his reign. This would place the year of his birth approximately at 560, and he would not then have been able to marry until the mid 570s. According to Gregory of Tours, Charibert was king when he married Ingoberg, Bertha's mother, which places that marriage no earlier than 561. It therefore is unlikely that Bertha was married much before about 580. These later dates for Bertha and Æthelberht also solve another possible problem: Æthelberht's daughter, Æthelburh, seems likely to have been Bertha's child, but the earlier dates would have Bertha aged sixty or so at Æthelburh's likely birthdate using the early dates.