Now who has a sling? Right, see giant Goliath in the next picture to make certain this is David.

I have been informed: "The upper left inscription, refering obviously to the person in the circle, says "Samouel Margare" (the prophet Samuel).
Lower inscription: "Savough t'agavor" (King Saul).
You have left only half the upper right inscription in the picture, and it says again "MARGARE", that is, Prophet (David probably, before meeting Goliath)."