Complex sentence: In 1898 she married the poet/publisher Paul Dunbar in New York while she was teaching at the White Rose Mission (White Rose Home for Girls) in Harlem, which she had co-founded.
Split into simpler sentences: In 1898 she married the poet/publisher Paul Dunbar there. She was teaching at the White Rose Mission (White Rose Home for Girls) in Harlem, which she had co-founded.