Complex sentence: Sarah was one of twenty-two delegates to represent Pennsylvania at the first Anti-Slavery Convention of American Women held in New York City in 1837 and was selected to be one of the convention's secretaries.
Split into simpler sentences: Sarah was one of twenty-two delegates to represent Pennsylvania at the first Anti-Slavery Convention of American Women held in New York City in 1837. She was selected to be one of the convention's secretaries.