This is an excerpt from Libro di cucina / Libro per cuoco
(Italy, 14th/15th c. - Louise Smithson, trans.)
The original source can be found at
Louise Smithson's website
XXXIII - Jelly ready to serve and good of fish. To make jelly of fish for 12 persons, take three large tench, take two ounces of sweet and strong spices together and half a quarter of saffron for this, and take the fish well washed and put in the sun a little, take and cook in part water, part fine vinegar, and set them to boil. And when the are well boiled, the first thing that you add, is the said spices and saffron and everything, and set to boil softly and very closed. When it is cooked pull it off and set it to cool, have bay leaves well washed and powdered with the said spices, and then take the fish and place in the vessel and let rest the jelly. Either boil the saffron or not. When it is chilled and a little set, put it over the fish and put enough spices and it is done, etc.
Other versions of this recipe:
A gilly of fleshe (A Noble Boke off Cookry)
Gelye de Fysshe (Two Fifteenth-Century Cookery-Books)
Fish Jelly (Du fait de cuisine)
GELE OF FYSSH (Forme of Cury)
Gelee of fysche (Fourme of Curye [Rylands MS 7])
Gely of Fysh (Thomas Awkbarow's Recipes (MS Harley 5401))
Gele of fysshe (Ancient Cookery [Arundel 334])
If you want to make fish jelly (Enseignements qui enseingnent a apareillier toutes manieres de viandes)