This is an excerpt from The Neapolitan recipe collection
(Italy, 15th c - T. Scully, trans.)
The original source can be found at
University of Michigan Digital General Collection
Slavic Cooking Sauce or Serving Sauce: Garlic Sauce. Get good walnuts and grind them; when ground, add in as much garlic as you wish; then get a crustless loaf of white bread and soak it in broth, grind it again and distemper it with broth; make up small bowls with pepper on top. If you want it yellow, add saffron; if you want it peacock-blue, add black grapes or cherries -I mean, their juice.
Note that in grinding walnuts, or even almonds, you should always add a drop of fresh water or rosewater into the mortar as you grind.