Unknown Silver Pfennig - Bishop - Star with letters ?

[aidab]

Hi,

This silver piece weights around 0.6 gr and it's diameter is around 16 mm. It shows an bishop ? bust in one side and a cross with four letters/symbols (N-S-?-?), each one at the end of the 4 star arms surrounded by a hardly visible legend in outer circle.

I would appreciate any help to identify it.

[Salier]

Hallo Aidab,
Würzburg Bistum, Hermann I. von Lobdeburg 1252-1254., Brustbild mit liegendem Schwert und Buch / Brunomonogramm. Ehwald 3801, Slg. Piloty 839.

Gruß
Salier