Where Did The Phrase "Whatever Suits Your Fancy" Originate?

Your fancy can be taken to mean, your likes, your wants, or desires. So the evolution of the term "whatever suits you fancy" really is self explanatory. Just like when we  use the expression to fancy something, or someone. Used as a present simple verb, I fancy John, or, John fancies me. Or I fancy an ice cream.
It simply means to like or want.
So to say "whatever suits your fancy" evolved with the language naturally I imagine.
Another way of saying "do whatever pleases you," or "do as you please", however these two have come to have a more sarcastic ring to them
So instead we say, "whatever suits your fancy", or "as you like."
not to be confused with fancy the adjective, which means elaborate or richly decorated, or even elegant.