Probably Italian, late 16th century
TRIPTYCH WITH THE VIRGIN AND CHILD AND ATTENDANT SAINTS
with a faint Austrian customs stamp to the reverse: Vom Bundesdenkmalamt z[...]
engraved and blackened bone, in a velvet lined leather bound box
central panel: 21.5 by 16cm., 8½ by 6 3/8 in.
side panels: 20.5 by 8cm., 8 1/8 by 3 1/8 in.
box: 24 by 19cm., 9½ by 7½ in. (closed)
Private collection, Switzerland