Medieval recipe: Pears in Syrup

Every now and again I have a go at a recipe from the ancient or medieval worlds, officially for research purposes but mostly through a mixture of curiosity and greed. Since I now own a copy of Constance Hieatt's delectable book of authentic medieval recipes, Pleyn Delit, this time it was one of those deceptively simple but spicy, wine-warm sweets which the fourteenth and fifteenth century loved.

The recipe calls for 1 kilo/2 lb of pears, 500ml red wine, 1 tbsp. red wine vinegar, 125 gm sugar, 1ts