Roman bread

[Gaivs Antonivs Satvrninvs]

One of my commilitones always tries to bake bread in an open fire. He places the dough on a flat stone, covers this with a ceramic bowl and shovels some coals over them.

This sounds like the right approach except for adding the coals over it.
The bowl covering should be, I believe, unglazed because the glazing would increase the heat. You want something similar to a Romer-topf.

Here's a few recipes that you can try at home. Some are pretty good.
Please let me know if you try them and your opinions.
http://www.romans-in-britain.org.uk/arl ... lasses.htm