Complex sentence: The oldest Lutheran church in Chicago, Illinois was an Evangelical Synod congregation--the "German Evangelical Lutheran St. Pauls Congregation", founded in 1843 and now known as St. Pauls United Church of Christ.
Split into simpler sentences: The oldest Lutheran church in Chicago, Illinois was an Evangelical Synod congregation. The "Deutsche Evangelische Lutherische Sanct Paulus Geminde" (German Evangelical Lutheran St. Pauls Congregation) was founded in 1843 and now known as St. Pauls United Church of Christ.