"Durante bene placito regis" is a Medieval Latin term that has the meaning of, in saying: "
no one could hold an official position against his (the Kings) will"
The site that had it said that it means "
during the pleasure of the king"
Durante means during of course, bene is well, placito is in the ablative case however, and regis is obviously genitive.
Is Durante causing placitus to take an ablative form? Would it mean: "Durante placito regis", "during the pleasure of the king"? If so, what is bene doing for "Durante placito".
Maybe with the words having shifted place: "Bene durante placito regis"; Well/appropriately/rightly during the pleasure of the king"?
So Durante bene placito regis, "Rightly during the pleasure of the king" as a way of saying "no one could hold an official position against the king's will".