Bronze item with raised feature. This piece has a beautiful Military Eagle with wings tucked in, head turned right and standing tall, beak pointing skyward. One fitting hole is still present on the bottom right and the remnants of one is on the left. Two raised ridges run vertically on either side of the Eagle. A dot pattern "O" can be seen where the beginning of a personal inscription would have been. A full piece would have had other figures/gods on it and was probably 15cm long.
Although there are similar examples in the following references, there are two opinions on their function. The first and oldest is as follows:
Most likely part of an elaborate decorative Cavalry breast plate. This armor was worn by the Cavalry unit when dressing up for their “Hippika Gymnasia” which was a sort of sporting event. This event utilized skill in weapons, spear throwing and numerous other warrior feats on horse. This was all done with specially decorated armor by the 3rd Century AD. This armor would never have been worn for combat, but used in these events alongside the standard chain mail/scale mail. (1)
The second and more recent opinion:
The two symmetrical bronze pieces (Bertoldsheim plates) took the place of the Mail hooks previously used (see HERE). These highly decorated pieces would help close the mail/scale mail across the chest and provide a tight fit around the neck. They used a system of rivets and square pins to fasten to the armor. This meant that many of the legionaries or cavalry soldiers would have used this system to fasten their armor if they still employed mail or scale mail. This type of armor came back into fashion later in the 3rd Century and beyond. (2)(3)
-painting by M. Daniels
The following are a couple of examples of Museum pieces, which are nearly completely intact.
Here is a more detailed sketch of a similar item by Mike Bishop.
Click on Pictures for higher resolution
Close up View
(1) References to similar items: FEUGERE, Michel; Weapons of the Romans, page 152-152 (first published in 1993)2002.
(2) References to similar items: STEPHENSON, I.P; Roman Military Equipment "The Later Empire", page 35-38 2001.
(3) Reference to similar items: BISHOP, M.C & COULSTON, J.C.N; Roman Military Equipment "From the Punic wars to the Fall of Rome", page 119 2006.
**Note on background. Close up view of the wall of the Colosseum of Pula, Croatia. Picture taken 2014