Siedenburg as a Place:
Siedenburg, Kr. Diepholz
Siedenburg ist ein Flecken im Landkreis Diepholz in Niedersachsen.
A trade name:
Siedenburg - to boil salt later to trade in salt
A trade name
Siedenburg silk trader
Sieden - came to mean old-dandy .... From: German Names by Hans Bahlow
I did find some mention of a famous silk trader with several houses
Including one in Prague
And German search engine:
http://meta.genealogy.net/Search.do;jsessionid=9DF641D24F5B598E292F072239676
28C
Hope this helps in some way
Pam Arkansas