The 14th-c. Catalan Libre de Sent Sovi gives a recipe “to make mustard our way”, with finely ground mustard seed, broth, and honey or sugar, pointing out that “the French style” is tempered with vinegar rather than broth. The 13th-c. Arabo-Andalusian “Manuscrito anonimo” gives the following recipe for “Sinab“:
Clean good mustard and wash it with water several times, then dry it and pound it until it is like antimony [powdered]. Sift it with a sifter of hair, and then pound shelled almonds and put them with the mustard and stir them together. Then press out their oil and mash them with breadcrumbs little by little, not putting in the breadcrumbs all at once but only little by little. Then pour strong vinegar and eggs over this dough for the dish, having dissolved sufficient salt in the vinegar. Then dissolve it well to the desired point, and clarify it thoroughly with a clean cloth; and there are those who after it is clarified add a little honey to lessen its heat. Either way it is good.
If recalled correctly, a 13th-c. Anglo-Norman source also describes a mustard sauce and specifies its particular affinity for pork.