Redburga or Raedburh was the wife of king Egbert of Wessex and may have been the sister-in-law of Charlemagne as the sister of his fourth wife, Luitgarde; other sources describe her as his sister (although Charlemagne's only sister was named Gisela) or his great-granddaughter (which would be difficult to accomplish in the forty-six years after Charlemagne's birth) or the daughter of his sister-in-law or his niece. Some genealogies identify her as the granddaughter of Pepin the Short and great-granddaughter of Charles Martel; other scholars doubt that she existed at all, other than as a name in a much later manuscript.

According to some accounts, Charlemagne arranged Raedburh's marriage to Egbert in the year 800. Egbert, who had been forced into exile at Charlemagne's court by Offa, King of Mercia, returned to England in 802, where he became King of Wessex and later king of all England. Raedburh's son Ethelwulf succeeded Egbert. Raedburh was also, according to this version of events, the grandmother of Thyra Dannebod Queen of Denmark, who was the wife of the Viking King Gorm "the Old" of Denmark and the mother of Harald Bluetooth Blataand King of Denmark.

Confusing matters still further is the rival tradition that Raedburh survived Egbert, who by these accounts died in 811. This individual devoted her life to helping the poor and became known as "Saint Ida of Herzfeld". Among her reported acts of kindness were filling a stone coffin with food each day, then giving it to the poor; she also reportedly founded the church at Hofstadt, Westphalia, and the convent of Herzfeld, sometimes recorded as Herford or Hervorden. where she is buried. She was canonized on November 26, 980, is the patron saint of brides and widows and is frequently depicted either as carrying a church or with a dove hovering over her head.

It appears, however, that this Saint Ida was married to a different Egbert, a duke of all Saxony between the Rhine and the Weser appointed by Charlemagne. Unless the Egbert reported in the Anglo-Saxon Chronicle to have regained his throne in Wessex in 802 was, in fact, serving instead as a feudal supporter of Charlemagne in Saxony for many of the years following his return to Wessex, Saint Ida was not the Raedburh who married Egbert of Wessex. Given the irreconcilable differences in the dates of death given for these two Egberts, that conclusion appears more likely.

This Egbert and Saint Ida are reported to be the parents of Warin, the abbot of Corvey from 826 to 856, Count Cobbo the Elder, and Addila or Mathilde, the abbess of Herzfeld; others suggest that a Saxon duke Liudolf, grandfather of Henry the Fowler, was also a son of Egbert and Ida and that Mathilde was their granddaughter.

References

Lives of the Saints:(www.catholic-forum.com/saints/sainti14.htm)

Essay on the relationship between Egbert and Charlemagne:(archiver.rootsweb.com/th/read/GEN-MEDIEVAL/1998-12/0912872813)