 The story of Beorhtwulf 's other known son , Beorhtfrith , is told in the Passio sancti <unk> , which may include material from a late 9th @-@ century source , with some corroboration in the chronicle of John of Worcester . Beorhtfrith wished to marry the royal heiress Ælfflæd , King Ceolwulf 's daughter , widow of Wiglaf 's son Wigmund and mother of Wigstan . Wigstan refused to allow the marriage , since Beorhtfrith was a kinsman of Wigmund 's and was also Wigstan 's godfather . In revenge , Beorhtfrith murdered Wigstan , who was subsequently venerated as a saint . The story , though of late origin , is regarded as plausible by modern historians . 
