Complex sentence: He later came to know a prominent leader in the movement, Alexander Campbell who encouraged him to become an evangelist, spending his time travelling around the eastern States of America preaching, until eventually settling down as a preacher in Philadelphia.
Split into simpler sentences: He later came to know a prominent leader in the movement, Alexander Campbell, who encouraged him to become an evangelist. He spent his time travelling around the eastern States of America preaching, until eventually settling down as a preacher in Philadelphia.