This was a beehive- or barrel-shaped container of baked clay, usually divided into two by a central horizontal partition.
The lower section formed the fire-box in which were burned pieces of dried wood, foten taken from the Nile, or even dried animal dung.
The oven opening was closed with a large stone, sometimes sealed with clay.
Ovens which worked on this principle, but were constructed of bricks or small stones, may still be seen in the ruined city of Pompeii.
In Jerusalem there was a bakers' quarter where bread was baked in tiers of stone-built ovens, or furnaces as they were called in the Bible.
In Ancient Rome bread ovens in the public bakeries were originally hewn from solid rock.
These ovens were heated by the familiar method of burning wood in the baking chamber, raking out the ashes and putting in the dough to bake.
There is an alternate theory regarding the invention of brewing.
Some historians believe it is possible that brewing began when the first cereal crops were domesticated.