It is a Balkan miquelet, probably Albanian or Northern Greek, say around 1800-1830. Arrowsmith is quite right, it is a kubar or horse pistol. Place of manufacture could be Istanbul, or any one of the smithing centers in the Balkans. Equally probable is that it came out of Brescia or Liege. The Ottomans imported a lot of guns from Europe, who were tripping over themselves to supply indigenous style firearms to North Africa, the Middle East, Turkey, and the Balkans.