I really think that scoring the loaf after raising (their method) looks nothing like the either the carbonized loaf from Pompeii or the fresco shown. What they look like is more akin to sectioning with something blunt, either with twine or a piece of wood.
Not to cut the sections, but to divide them so it can be pulled apart easily without a knife. It would be undesirable to actually cut the "skin" of the loaf. Then as they suggest, wrap twine around the circumference to pull it back together. The result would be more like a batch of rolls that can be pulled apart.
It makes sense they'd want to sell a loaf that can be easily eaten without a knife. Just scoring the loaf as they show doesn't give you a loaf that tears apart, the scores end up being just decorative and bakers do that to avoid a split when it bakes.
It doesn’t take much real bread to turn people away from the mass produced options.
Soughdough is surprisingly forgiving and can be made in a pretty lazy fashion with excellent results - just keep deleting steps in the recipe until it doesn’t work, then go back one step.
Just don't confuse it with real bread and you'll be fine!
Then they would simply lay the net on the dough before letting it rise or before baking it. The bread expanding sideways when rising would first hold the rim into place and make the straight strings taunt, which would then leave their mark on the bread.
No slow and complicated tying, no unexplained lateral groove, and an easy way to ensure that each loaf is the same size while also making convenient slices.
Then look at this picture, there the loaves have a lot more sections, and that seems completely impossible to tie by hand for each piece of bread. However, they could be ready-made and with just one opening on the rim, to tie before laying on the loaf (which would be easy, and could be done during off-time when waiting for the dough to rise or other loaves to bake, for example) and to untie after baking to allow removing the net.
However, they also had locally-produced linen (the classic Roman tunic was made from linen) and linen is considerably more heat-resistant than cotton.
If you have a steam iron handy, take a look and you'll see that the ironing temperature for linen is higher than that for cotton.
I'm thinking, it doesn't have to be very strong, and if you can't reuse the twine anyway...
> bakers do that to avoid a split when it bakes.
I know from experience that slashing an under-proofed, or appropriately-proofed loaf allows it to rise more than if it weren't slashed.
Although it doesn't have the eight slices of Panis Quadratus, it does have the distinctive ridge in the middle, formed by taking two circular discs of dough and pressing them together with a stamp.
This seems to me at least as likely of a theory for the ridge in the middle, as wrapping a bit of twine around it solely for the purpose of making the indentation.
Maybe that's not surprising - there aren't really that many ways to make bread - but it's interesting how old these recipes are.
In that case it would be informed by modern practice.
I'd have to imagine slap-and-fold is a pretty old technique, even if why it worked would be as mysterious as the leaven itself.