Benjamin and William(Butler)Masters

I am looking for information on a Benjamin Masters from PA(I believe). He came to IA during th late 1800's and a descendent married named Ellen Masters married Johnathatn Clark Washburn. They had several children and I am the granddaughter of their oldest, "Josie" Washburn.
William(Butler)Masters is the grandson of Benjamin. He is part Native American(mother Josephine Masters, daughter of Benjamin, and father was ? Butler). If anyone has information please contact me. Thanks