I know when they married (1907)- Blanche was 18, so it was after July 4. Blanche was born 7/4/1889. She started out Catholic as a child, but later became Methodist.
According to what she wrote on a badly deteriorated paper, they were married in Pittsburgh, PA at Smithfield Ave. church by Rev. Fletcher Wharton.
Her mother Margaret Jane Ransel died when Blanche was 10, and her father John Joseph Slater wasn't around much after that.
I've written to the archive for the Smithfield Ave. Methodist Church, and while there was a Fletcher Wharton they have no record of the marriage. Butler County also shows no marriage license being issued.
We know nothing about William except his death date (3/30/1912) and the fact that his death certificate is on file. I am waiting for a copy of that to see what it offers. My other alternative seems to be to write to each county that Blanche lived in (including Butler).
So anything that points me in the right direction would be a HUGE help!