Bronze Crossbow style Fibula/pin used to hold together the Toga/clothing of the Roman Soldier and Citizen.  Called Crossbow due to its unique shape similar to a crossbow.  This example however is somewhat unique.  It has an iron segment that constitutes the cross piece, ending in two bronze spheres.  The point of the fibula where the remnants of the iron spring and pin are has a curled bronze piece.  The arch has small dots engraved on it while a bronze segment is wrapped around at the end of the arch. The arch would have been where the fabric bunched while the pin secured it.  In the flat section there is a dot pattern border that surrounds it.  Within this border is a Greek inscription

M I X A I A

This simply states "Mikail" of Michael as the name is known today. 

That fact that it is inscribed in Greek indicates that it perhaps was part of the East Roman empire which largely spoke Greek, and fully Greek by the time it became the Byzantine Empire.  (1)

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Underside View