You might be offered oatcakes as well as bread (especially in the north). If these do not tempt you, consider eating "horse-bread." This is made from a sort of flour of ground peas, bran, and beans–if contemporaries look at you strangely, it is because it is not meant for human consumption.
Ian Mortimer, The Time Traveller's Guide to Medieval England: A Handbook for Visitors to the Fourteenth Century
bread, food, history, medieval-england