there are a lot of people who do not believe king solomon was a real person, but instead the (literary)vessel for the knowledge in the keys, and that this name was chosen for two reasons. 1) that the author could escape persecution by placing what might be seen as blasphemous writings at the hands of a jew, and 2) because his name does indeed formulate a correlation to sol, or the sun. in fact one of the accounts of the king was called "the song of sol". now this is a theory and its not one i am proposing as my own, it is just a theory that is present in the metaphysical as well as cultural anthropological debates.
there are still other people who think it is possible that the figure of king solomon took 72 magi and told them each that if they would create him a "servitor", and then be killed, he would allow their families to have land, and monies, and live in affluence for the rest of the time that the families name lived on. if they did not do this, then he would kill them AND their families. so these magi created 72 servitors to serve the king and their own energy was the source for the beings they created, and their death as a sacrifice allowed these servitors to live on, but the magi created the servitors to eventually destroy solomon(which as the story goes happened). now the 72 goetic beings are actually these same servitors. that is a more off the wall theory but interesting none the less.
i would study the Shemhamphorasch for a better understanding of the goetia.