drinking vessels

[Mark Harris]

I. Marc Carlson said:

 Sure, we know they had them, we find cup sherds all the time,
(actually, we find sherds all the time, but I need to check the kind)
but often I'm led to believe that some people used whatever was at hand
including a picture of a feast in de Foix that clearly shows only ONE cup
being used by one of the thirteen people in the picture (and he appears 
to be one of the servants) while two of the others are shown drinking from 
costrels, with other costrels lying about. 

>>>>>
Stefan li Rous want to know: "What is a costrel?"