The Annals of King David

King David is arguably one of the most enigmatic figures in the Bible. His story is described only in the Bible where he ranks third in the amount of dedicated space after Moses and Jesus of Nazareth.
Did he even exist? Is there any other evidence to support his story? Most of the evidence for his life is to be found in the Old Testament of the Bible. Why is he so revered as the ideal theocratic monarch? Was he a man of his time or a ruthless, scheming tyrant?
There is much to admire about the person of David and much to be frightened by. This story tells the biblical version of events through his own eyes towards the end of his life. It is therefore apologetic by definition.