Lady Finella lived from about 950 to about 995. Also known as Fenella, Finuela, Finnguala, Fimberhele or Sibill, depending on the source, Lady Finella is remembered for murdering King Kenneth II in 995 in Fettercairn. The wider picture in Scotland at the time is set out in our Historical Timeline.
Lady Finella was the daughter of Cuncar of Angus, the Mormaer or Earl of Angus: a line probably descended from Pictish royalty. Most of what we know about her comes from references to her in the chronicles written by John of Fordun in the late 1300s, which in turn were probably based on folklore then current in Angus, an area which he knew well.
It seems that Lady Finella's son was killed, probably in battle, by King Kenneth II and she set out to take her revenge. According to one of the less believable aspects of the story, Lady Finella constructed an elaborate trap in a cottage near Fettercairn, into which she then lured Kenneth II as he visited the area. In the centre of the main room stood a statue of a boy. When the king, at Lady Finella's urging, touched the statue's head, it triggered a series of concealed crossbows hidden around the room, whose bolts then killed the king.
Setting aside the fanciful means of the assassination, it does seem clearly established that Kenneth II was killed in Fettercairn. in 995, and it is possible he was killed by Lady Finella. The story continues that, having killed Kenneth, Lady Finella fled towards the coast. She was eventually cornered by Kenneth's men in a valley with a waterfall near St Cyrus. Today the valley is marked on Ordnance Survey maps as "Den Finella", and according to the chronicles, it was here that Lady Finella threw herself to her death from the top of the waterfall to avoid capture.