What you have on the dagger appears to be a coin minted in the Ottoman empire as it carries what appears to be a Tughra, in other words the Sultan's emblem in the shape of an elaborate calligraphic composition which contains his name and imperial titles. The Tughra may shed a light on the period the coin was minted but the picture is a bit too small. But mind you, Tughra writing is not easy to read.
I'm no expert on Turkish history and coinage, so can someone help?
