Complex sentence: Also, there were a lot of Mennonites originating from the Vistula Germans who had lived in West Prussia since the Ostsiedlung.Prussia imposed heavy taxes due to their beliefs, they emigrated to Russia and became hence known as Russian Mennonites, speaking a Low German dialect called Plautdietsch.
Split into simpler sentences: Also, there were a lot of Mennonites originating from the Vistula Germans who had lived in West Prussia since the Ostsiedlung. Feed by Prussia with heavy taxes due to their believes, they emigrated to Russia and became hence known as Russian Mennonites, speaking a Low German dialect called Plautdietsch.