Complex sentence: Joseph, in turn, was the son of Samuel Church, who founded the first paper mill in Lee, Massachusetts in the Berkshires, and this allowed him (Frederic) to pursue his interest in art from a very early age.
Split into simpler sentences: Joseph, in turn, was the son of Samuel Church, who founded the first paper mill in Lee, Massachusetts in the Berkshires. The family's wealth allowed Frederic Church to pursue his interest in art from a very early age.