I think that the church records are the key.Just would have to know the name of the Greek Orthodox church in Sereth at the time, looking between 1850-1915. Is there any way to find out if a Greek Orthodox church still exists in Sereth, and if so, do they have any records I could access? I would be glad to pay for search and records. I did get records for my paternal ancestors from Belarus National Archives and traced ancestors back to 1690-- to present day. Thanks again for your interest and help.Much appreciated.