Well preserved bronze mail or lorica hamata hook in the shape of a serpent/snake. Once part of a matching pair that would have been connected at the center with a rivet.  In this case the remnants of that iron rivet still remain, as does the actual "Washer", seen as the indented circle in the iron remnants. 

This piece has a snake or serpent head with horns/eyes visible.  The item is covered in an even colored light green patina, however has remnants of some encrustations.  The most interesting feature of note however is the personal inscription on the reverse.  Roman soldiers commonly engraved their equipment, much like a modern day name tag.  It obviously was not uncommon for items to get misplaced or stolen and much of their equipment was valuable and one would not have wanted to loose it.  This means that many Roman military equipment artifacts that have survived to be excavated have been found with these inscriptions.  This aids significantly in identifying who the piece belonged to, which unit they were in, and what period they were alive. 

This item has the following crudely engraved inscription on the reverse.

XII VI

I believe this simply stands for the Legion number and Cohort number of the owner.

Legio XII Fulminata (the lightning legion), Cohort VI.

The history of Legio XII Fulminata can be found HERE, however of note is the following:

"In 75 (AD), the emperor Domitian sent out the twelfth legion to support the allied kingdoms of Iberia and Albania (in the western and eastern Caucasus)." 

This is very close to the area in which the item was found, Lake Ochrid Macedonia.  The site of a long standing Roman town/city.  If my assumptions are correct this does date this piece to some time around 75 AD.

Although the matching piece is missing, I can only assume that it would have had the name of the owner. One side with the unit name, the other with the owners name.

The following example (although of a slightly different style) also has an inscription.

(taken from http://www.rom-museum.de/start.htm which is a site in German)

These hooks were designed to decoratively and functionally hold the shoulder pieces of mail together across the chest on the early legionary. There were a variety of styles, with many being of the serpent/snake type.  These were eventually taken out of use by the 3rd Century in favor of a larger bronze decorative plate.  (See fragment of such an item HERE)

As lorica segmentata came into mainstream use mail or lorica hamata began to be phased out. It was expensive to make and had some distinct disadvantages for protection over the new plate armor. Later in the Roman period however (3rd Century onwards this trend again reversed and mail was again seen in use) (1)(2)(3)

-painting by John Warry

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