The evil stepmother did it

A sign in the little village of Corfe Castle in Dorset proclaims that Edward the Martyr, King of Wessex, was treacherously stabbed by his stepmother Elfrida (also Ælfthryth or Alfrida) in AD 978. What evidence is there that the evil stepmother did it? Well, none of course! Edward's reign was short, lasting less than three years before his violent death. Byrhtferth, writing around 1000, is an almost contemporary source. He describes the murder as an act of treachery but does not name Ælfthryth as responsible: One day towards evening the remarkable and elected king, seeking the consolations of brotherly love, arrived at the house where his beloved brother was living with the dowager queen, as we have said. The magnates and leading men went to meet him, as was only fitting; he [the younger son] remained inside with the dowager queen, his mother. Those magnates had agreed among themselves a wicked plot: they were possessed of so damnable an intention and so murky and diabolical a blin...