Complex sentence: In 1855, the non-Mormon resistance succeeded in getting the Michigan Legislature to reorganize the County of Emmet with the islands, including Beaver Island and North and South Manitou Island, set off into the separate Manitou County, which effectively eliminated Mormons from Emmet County government.
Split into simpler sentences: In 1855, the non-Mormon resistance succeeded in getting the Michigan Legislature to reorganize Emmet County. The islands, including Beaver Island and North and South Manitou Islands, were transferred into the separate Manitou County, which effectively eliminated Mormons from Emmet County government.