Sewage, including Medieval treatment and why it was valued in Japan and a nuisance in Europe

Well, you can use humanure safely, you've just got to treat it correctly and leave it for long enough to be safe - talking getting it up to a good heat during the decomposition and also then waiting a year or more for pathogens to die just to be safe. There is also a difference between using it to fertilize trees and plants like tomatoes, vs root veg - because the latter come in direct contact with it. Or you can use it on grass growing, for grazing animals.

There is an article with links here on how to safely use humanure.

And my original link at the end of the article in the contemporary part also gives a number of outfits using different methods to safely handle humanure.
I'd also note that reading Annie Hawes books on life in Italy, that it was common to have the tomato patch in the extra rich area of ground next to the cess pit - which was slowly leaching out nutrients. In Johnny Morris's book "There's Lovely" the contents of their outdoor toilet can was buried in a trench in the neighbour's garden. My late father used to talk about the corporation muck-cart - would come down the back lane and empty cans into a big cart. Don't know where it all went to.

Other than that, it is interesting how the drivers of poor soil such as in Japan and at Mount Vernon affect attitudes to composting (though Mount Vernon is just talking about horse manure).