Bird-shaped Pendant with Brown Wings (Toy) 13th century The exact function of these glass birds is not known. The loop on the backs of some of them suggest that they may have been suspended; the rattling rods found inside indicate that they were perhaps chimes or toys. Many of these birds are decorated with marvered trails, usually white on a manganese-purple ground.. Bird-shaped Pendant with Brown Wings (Toy). 13th century. Glass, green; blown, applied opaque red decoration. Attributed to Syria. Glass