When William Kennedy Smith was on trial for rape in Florida I didn't understand how he was related to the Kennedys and could be a first cousin to JFK, Jr. I knew that Kennedy was his middle name, but I didn't realize until later on that many individuals are named for their mother's family. Dr. Smith's mom is Jean Kennedy-hence his middle name Kennedy.
I also still confuse Mary Wollstonecraft and her daughter Mary Wollstonecraft Shelley since their names are so similar. At one time I thought that they were the same person.
A childhood belief about names

others believed things like this
- I used to believe that Will Smith's name wasn't Will Smith, but that it was World Smith.— Scott
- I used to think "Aero Smith" was only one person.Anon
- For along time I thought the Middle East and Eastern Europe were just different names for the same place!— Helllowerer
- I thought "Virgin Mary" was actually "Verge 'n Mary" and that Verge was a nickname for Joseph. — Rachel
- I used to think virgin mary was actually 'virginia mary'Anon
- When my cousin was younger his name was Alexander and he thought his middle name was "ander"Anon