response: yeah it was a medicinal food source as well
history: Kale is so good for you. I try to eat it every day. Nice!  I know that kale leaves don't make a head, like headed cabbages do.  Also, their leaves can be purple or green! Oh cool.  Do you know anything about the history of kale? Well, in Europe it was very common up until Middle Ages' end.  In fact, of the green vegetables, it was the most common! Wow! I guess it's a really hardy plant I actually don't know about that.  But even further back, in the 4th century BC, curly and flat leaved types of cabbage were known to already exist, in Greece. Interesting.  Does it have any health benefits?
knowledge: It was also used as medicinal food source.