This is an authentic medieval, ca.500 years old,  Guardian Angel Pilgrims badge,  with a Martyr saint on the obverse who I haven't identified yet, these were worn by Pilgrims to Rome, The Holy Land or on the Camino or one of the other many old pilgrimages the faithful make.  I will say it's bronze (or a similar alloy ). Dimension: 31mm  ( 1 1/4 inch long) this could be still worn to make a unique piece of jewelry. Comes from an old South German collection.