The article below is an excerpt from Wikipedia on Russian Mennonites. My family did not come from this line and I never learned about the history in Russian. Do any of you speak Plautdietsch?
The Russian Mennonites are a group of Mennonites descended from Dutch and mainly Germanic Prussian Anabaptists who established colonies in South Russian Empire (present-day Ukraine). Since the late 19th century, many of them have come to countries throughout the Western Hemisphere. The rest were forcibly relocated, so that few of their descendants now live at the location of the original colonies. Russian Mennonites are traditionally multilingual with Plautdietsch (Mennonite Low German) as their primary language.
In the early-to-mid 16th century, Mennonites began to move to Russia seeking religious freedom and exemption from military service. They gradually replaced their Dutch with the Plautdietsch dialect spoken in the area, blending into it elements of their native tongues. Plautdietsch is the distinct Mennonite language which developed over a period of 300 years in south Russia.
Catherine the Great of Russia issued a Manifesto in 1763 inviting all Europeans to come and settle various pieces of land within Russia, especially in the Volga River region. For a variety of reasons, Germans responded to this in large numbers.
When the Prussian government eliminated exemption from military service on religious grounds, the remaining Mennonites were eager to emigrate to Russia.
It is interesting to note that this settlement of Mennonites in Russia was at the same time that Mennonites were also moving to America for similar reasons.