This is an excerpt from Le Menagier de Paris
(France, 1393 - Janet Hinson, trans.)
The original source can be found at
David Friedman's website
Mussels are best at the beginning of the new season in March. Cayeux mussels are red, round crosswise and longish, and the Normandy mussel is black.
Other versions of this recipe:
Mussels (Le Viandier de Taillevent)
MUSSELS are cooked quickly on a high fire (Le Menagier de Paris)