A Rus or Russian Viking Belt Buckle. Based on a belt mount. From an exhibit "Ibn Fadlan's Journey: Volga Route from Baghdad to Bulghar" in a Moscow Museum. Several other pieces show about 35 mounts on a belt. Available here
http://raymonds-quiet-press.myshopify.com/products/viking-belt-mount-25-of-rus-n-79
8th - 9th C. 2 1/4" x 1 1/2" 5.7 x 3.8 cm