Complex sentence: As curate of Olney, Newton was partly sponsored by an evangelical philanthropist, the wealthy Christian merchant John Thornton, who supplemented his stipend of £60 a year with £200 a year "for hospitality and to help the poor".
Split into simpler sentences: As curate of Olney, Newton was partly sponsored by John Thornton, a wealthy merchant and evangelical philanthropist. He supplemented Newton's stipend of £60 a year with £200 a year "for hospitality and to help the poor".