thanks frogpatch, the crown and the form of the coat of arms doesn't look english to me.
i just received this back from sothebys.
"The inscription definitely seems to be in Cyrillic, but the coat-of-arms
doesn't fit with Russian heraldry. It could be from areas now called
Bulgarian, Ukrainian (or a border area that could be Ukraine or Poland now),
Serbian, or Macedonian. If it is indeed Cyrillic, it looks like Zuoch
(Зуоч) or Zuol (Зуол). I searched both and couldn't find anything. I would
pursue Ukrainian sources first, since it seems most likely."