Quit saying there is no mystery! There totally is one!!!
Roanoke says hi. I mean, yeah, sure, they clearly just told the colonists they thought had abandoned them where/with whom they were leaving, and sure, there's a tribe of Native Americans with blonde hair and blue eyes not all that far from the region, but, you know... a total mystery! OooOoooOoOOOOooOoooh!
Ancient Astronaut Theorists belie... okay, sorry, I can't even finish vomiting that up.
You forgot the best one Jack the Ripper was a man from space. I mean its also a plot for a Star trek and balylone 5 episode, but you have no prouf he was not. So what if he was?