Complex sentence: First established in Jackson and other cities in 1854, it gathered together anti-slavery elements from the Whig, Know-Nothing and Democratic parties, and was a majority in Michigan by the end of the decade.
Split into simpler sentences: First established in Jackson and other cities in 1854. It gathered together anti-slavery elements from the Whig, Know-Nothing and Democratic parties, and was a majority in Michigan by the end of the decade.