I'd go easy on some of the ingredients mentioned in the Playwrights Bread,
i.e.ground oak bark, beech bark, ivy leaves. I've been into herbs for many
years and while the ingredients in the recipe may have been used in
mythology, I have never heard of them being safely used in foods that are
to be ingested. Certain parts of many plants are safe to use, while other
parts of the same plant are very poisonous.
For instance, use the delicious rhubarb stalks to make pies and jams, but
don't even think about using the green leaves for anything but boiling them
in an aluminum pan to clean the pan. They are highly poisonous.
The only ingredients in the herb family in this recipe that are safe by
today's standards are the Basil and Star Anise. St. John's wort
maybe. Until you can ascertain with absolute certaintity that the complete
list of ingredients is safe for human consumption no one should even think
about using them in bread baking. Tree barks were often used in dying
because of their high tanin content. Check with the Herb Society of
America on your ingredients for safe consumption.