I have a recipe for bread that's not at all period but it is medieval-esque. It makes 1 loaf.
2 cups rye flour
2 cups white flour
1 cup wheat flour
12oz Dark beear (porter or stout; Guinness works well)
1 packet yeast (if it's expired, it won't work)
2 tspn salt
2 tbsp honey
1 egg beaten
Let the beer go flat and mix in the packet of yeast. Let sit for 5 minutes or until foamy. Add the beaten egg, honey, and salt and mix well, but not too hard (don't disturb the yeast).
Add the flour mixture 1 cup at a time, stirring constantly. Work it in until dough form one cohesive mass that pliable, but not sticky.
Preheat oven to 200 degress. While oven is preheating, knead the dough vigorously for five minutes (Do not over-knead). Once ready, turn off the oven and place the dough in it with a moist towel over it. Allow dough to rise in the warm oven for 1 hour. Take out risen dough and compact it (be careful not to knead it, just push it down a little). Set it aside at room temp and let it rise for two more hours.
Preheat oven to 450. Once dough has risen cut a cross in the center and place in the oven. Let it bake for 30 minutes. Take out and let cool for 15 minutes then serve.
The resulting bread will have a very hearty taste and a dense texture.