65% think King Arthur really existed
58% think Sherlock Holmes really existed
51% think Robin Hood really existed
47% think the Eleanor Rigby of the Beatles song really existed
47% think King Richard the Lionheart is fictional
27% think Florence Nightengale is fictional
23% think Winston Churchill is fictional
Now admittedly, there are scholars out there who posit various real-life origins for King Arthur and Robin Hood, so there's some wiggle room for confusion on those two, but otherwise, I have to wonder how many of these people are like the kid in Last Action Hero and think F. Murray Abraham (or Antonio Salieri for that matter) killed Mozart.
Feudalism: Serf & Turf