On another message board here, researcher John Corlett left a note in 1999 that recorded the marriage below. The message can be found at http://boards.ancestry.com/mbexec/message/an/localities.ceeu...
or by searching on the names in the message.
To summarize, Corlett says that George Nathaniel Koehler b. 6 Sept. 1856 in Breslau area, was one of several children born to Baroness Helene von Martinitz. He says that Koehler came to the US circa 1889. He was married to Francis [sic] Vlasak.
It has to be Frances, which is the female spelling. Corlett doesn't say whether they married in Breslau in Germany or in the U.S. Hope this will be helpful to someone looking for that line of the VLASAK family.