The original recipe in Middle English from 1390 is as follows:
Take crustes of brede and grynde hem smale. Do þerto powdour of galyngale, of canel, of gyngyuer, and salt it; tempre it vp with vyneger, and drawe it vp þurgh a straynour, & messe it forth.
(N.B. þ is equivalent to th)
Translated into modern English:
Take crusts of bread and grind them small. Add powder of galingale, of cinnamon, of ginger, and salt it; mix it with vinegar, and pass it through a strainer, & serve it.
Pour this onto roasted meats, especially game, beef or mutton. I prefer to make it with claret and red wine vinegar as was more usual in Tudor times. I do like this delicious sauce and may well be cooking it for Christ-tide.