You may know those books, but they seem interesting enough to be mentioned:

Apicius: Cookery and Dining in Imperial Rome. Edited and Translated by Joseph Dommers Vehling. This is the first English translation of Apicius de re Coquinaria, the oldest known cookbook in existence.

The Neapolitan Recipe Collection: Cuoco Napoletano Feasting as a window into medieval Italian culture By Terence Scully . Outstanding among these early cookbooks is the one written by an anonymous master cook in Naples toward the end of the 15th century. In its 220 recipes, we can trace not only the Italian culinary practice of the day but also the very refined taste brought by the Catalan royal family when they ruled Naples.

The Medieval Kitchen: Recipes from France and Italy . By Odile Redon, Francoise Sabban and Silvano Serventi. Translated by Edward Schneider. Original line drawings by Patricia Glee Smith. More than a mere cookbook, The Medieval Kitchen vividly depicts the context and tradition of authentic medieval cookery.

found on this site:
www.foodbooks.com/italian.htm

good luck

This is one of my favorite websites for period cookbooks:

www.poisonpenpress.com/cookery.html

You might be able to find something here.

-Katie