Of course, medieval (and earlier) cooks knew about the preservative effects of honey. Apicius writes, in the first century A.D. (in the Vehling translation):
To keep meats fresh without salt for any length of time: Cover fresh meat with honey, suspend it in a vessel. Use as needed; in winter it will keep but in summer it will last only a few days. Cooked meat may be treated likewise.Fourteen hundred years later, Apicius's countryman Platina wrote of honey (in the Falconwood edition of his De Honesta Voluptate):
To keep cooked sides of pork or beef or tenderloins: Place them in a pickle of mustard, vinegar, salt and honey, covering meat entirely. And when ready to use you'll be surprised.
It keeps bodies from decomposing and is considered best for preserving fruits such as apples, gourds, citrus and nuts.And the anonymous scholar(s) who wrote the 13th-14th-century Tacuinum Sanitatis (based on work of the 11th-century Arab physician Ibn Botlan) explained that honey "prevents the alteration of meats," among other useful properties.
Meanwhile, on the other side of the Channel, the 14th-century English cookbook Forme of Cury gave this recipe for preserving vegetables in a sauce of vinegar, wine, honey, and spices:
And on a related subject, congratulations to Lord Robert Abeille, recently admitted to the Order of the Manche for his study of medieval beekeeping.
Compost.Take rote of persel, of pasternak, of rafens, scrape hem and waische hem clene. Take rapes & caboches, ypared and icorue. Take an erthen panne with clene water & set it on the fire; cast alle thise therinne. Whan they buth boiled cast therto peeres, & perboile hem wel. Take alle thise thynges vp & lat it kele on a faire cloth. Do therto salt; whan it is colde, do hit in a vessel; take vyneger & powdour & safroun & do therto, & lat alle thise thynges lye therin al nyght, other al day. Take wyne greke & hony, clarified togider; take lumbarde mustard & raisouns coraunce, al hoole, & grynde powdour of canel, powdour douce & anneys hole, & fenell seed. Take alle this thynges & cast togyder in a pot of erthe, & take therof whan thou wilt & serue forth.