St. Helena Medal.
Médaille de Ste. Hélène.

     Created in 1857 by Napoleon III for issue to surviving soldiers of Napoleon Bonaparte's "Grande Armee"¹ who had served between 1792 and 1815.  It is Believed that 405,000 were issued. Obverse shows the bust of Emperor Napoleon I. Reverse inscription reads: "Campagnes de 1792 a 1815. A Ses Compagnons de Gloire sa Derniere Pensee Ste. Helene 5 Mai 1821" The designer was Albert-Désiré Barre, and his mark (an anchor) is below the bust. The medal has a height of 50mm excluding the ring, and is made from bronze . Ribbon 37mm wide, green with five red stripes and edges². The medal was nicknamed "the chocolate medal" because of its colour³.

Notes.
1. The medal awarded to the British enemy forces is here.
2. The ribbon is very similar to that of the WW1 Croix de Guerre, which is often used as a substitute.
3. The original applied patina is desirable and this medal should never be cleaned.