For example:
* What field of expertise was he in? (e.g., music, literature, science, sports, etc.)
* What was his approximate time period? (e.g., 19th century, 20th century, etc.)
* Do you have any other information about him? (e.g., his nationality, a specific accomplishment, a nickname, etc.)
The more information you can provide, the better chance I have of helping you find the right William Arthur.