Yes, I'm of Mennonite heritage and was raised in a Mennonite Brethren Church, as was my husband, so I'm researching many branches of our families. My gggrandmother Elizabeth Niebuhr was born around 1850 and married Gerhard Thiessen who died around 1912. To the best of my knowledge, they stayed in Russia, although all but one of their children came to Canada in the early 1900's. I only have information on my Thiessen branch--nothing on the Niebuhrs, but have been in contact with Bill Klassen in Winnipeg who's working on a Niebuhr book. If you don't already know of him, email me and I can put you in touch with him.