Cato\'s recipes

[Epictetus]

I have been wanting to try some of Cato's recipes for a long time. Because I'm completely inexperienced and not much of a cook I thought I'd try his recipe for libum, which is nice and simple.

Recipe for libum: Bray 2 pounds of cheese thoroughly in a mortar; when it is thoroughly macerated, add 1 pound of wheat flour, or, if you wish the cake to be more dainty, 1/2 pound of fine flour, and mix thoroughly with the cheese. Add 1 egg, and work the whole well. Pat out a loaf, place on leaves, and bake slowly on a warm hearth under a crock.

But I've immediately run into a problem. What kind of cheese should I use? I see modern versions of this recipe say ricotta, but I don't know where this comes from. I know some people make their own Roman cheese, but I don't want to get too fancy until I figure out what I'm doing.

Are there any suggestions of a cheese I can buy to use in this recipe?