Cookbooks, or more specifically, recipe collections, compiled in the Middle Ages are among the most important historical sources for medieval cuisine. The first cookbooks began to appear towards the end of the 13th century. The "Liber de Coquina", perhaps originating near Naples, and the "Tractatus de modo preparandi" have found a modern editor in Marianne Mulon, and a cookbook from Assisi found at Châlons-sur-Marne has been edited by Maguelonne Toussaint-Samat. Though it is assumed that they describe real dishes, food scholars do not believe they were used as cookbooks might be today, as a step-by-step guide through the cooking procedure that could be kept at hand while preparing a dish. Few in a kitchen, at those times, would have been able to read, and working texts have a low survival rate.