Who Were the Green Children of Woolpit?

Were they IRL fairies? AWOL aliens? Or maybe they were just… human?
 
In the 12th century, a brother and sister appeared in the village of Woolpit in Suffolk, seemingly out of nowhere. They were wearing foreign clothes and speaking a foreign language.
 
However, the most striking thing about the pair was the fact that they were both… green!
 
The villagers didn’t know what to make of this strange pair, but that’s possibly because they’d never heard of hypochromic aneamia – a rare condition that causes fatigue, a loss of appetite, and in severe cases, green-tinted skin.
 
So… were the Green Children of Woolpit actually otherworldly creatures, or were they Flemish settlers from a nearby village, ill and displaced after the Battle of Fornham?
 
(Let’s be honest, it’s probably the second one).
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https://www.youtube.com/watch?v=GYGH7MPdbU8