Romans were probably the first to experiment with the preparation of mustard as a condiment. They mixed unfermented grape juice, known as “must”, with ground mustard seeds (called sinapis) to make “burning must”, mustum ardens — hence “must ard”. A recipe for mustard appears in Apicius (also called De re coquinaria), the anonymously compiled Roman cookbook from the late 4th or early 5th century; the recipe calls for a mixture of ground mustard, pepper, caraway, lovage, grilled coriander seeds, dill, celery, thyme, oregano, onion, honey, vinegar, fish stock, and oil, and was intended as a glaze for spit-roasted boar. The Romans likely exported mustard seed to Gaul, and by the 10th century, monks of St. Germain des Pres in Paris absorbed the mustard-making knowledge…