I knew a Sistine back in high school. It's considered a feminine form of
Sixtus in the
Roman Catholic church. So I immediately have the image of a woman from a very devout Catholic background.
It's probably nearly impossible for most people in the USA not to think of the cartoon cat when they hear
Sylvester. It used to be that fan magazines regularly referred to Mr. Stallone by the nickname
Sly, probably because
Sylvester just didn't seem to fit his seemingly tough rugged image.