Iron buckle and copper-alloy plate

Iron buckle with bronze plate, l. 4.1cm. Oval iron loop, with [?] folded over it, a doubled triangular bronze plate, the back rather curved, the front with lower edges cut away angularly. Rivet holes in the front angles of he plate. The tongue is very odd indeed; iron, it appears to extend unbroken down the front length of the plate, and is certainly not pierced through the plate. Instead, the trace of an iron rivet at the end of the plate suggests it operated from there. Distinctly unusual.