Lucius Junius Moderatus Columella (4 AD to 70 AD) was a famous writer on Roman Agriculture. His work Res Rustica, written in 12 volumes, was discovered in monasteries in France and Switzerland in the early 15c. His recipe for the world's most famous condiment, is not so very different from the recipes of today:
"Carefully cleanse and sieve mustard seed, then wash it well in cold water. Leave in the water for two hours. Take it out, squeeze it in the hands, place it in a new or well cleaned mortar, and grind it with pestles. Then collect the whole mass in the middle of the mortar, and squeeze with the flat of the hand. Then scarify, place a few hot coals on it, then pour on water mixed with nitre, to leach away all its bitterness and pallor. Lift up the mortar at once for all the liquid to drain away. Add pine kernels as fresh as possible, and almonds. Grind finely, then adding sharp white wine vinegar, then strain. You will find this an excellent sauce for your dinner parties, and also attractive in appearance. If well made, it will be very brightly coloured."