Although I don't think I'd trust the 2000 year old variety, and Roman hygeine wasn't the greatest. Modern fish sauces are generally bottled using more sanitary methods.
You're right Cobwebs. It's basically the same as Nam Pla and has been compared to anchovy paste, which nobody thinks is all that outrageous. It got its bad reputation from the manufacturing process, which apparently smelled pretty objectionable, but was supposed to have smelled fine when it was completely fermented and properly stored.
My dissertation director, many years ago, was interested in a folding chair mentioned in an Old English Manuscript from, I think, the eleventh century, so he wrote to a scholar in England who was supposed to be an expert in Old English folding chairs. He got back a letter saying, sorry, I can't help you, my area of expertise istenth-century Old English folding chairs.
I didn't want to be critical, but I thought that people who were not artists or not familiar with artistic techniques might take it the wrong way, as if working from a preexisting image were inartistic in some way.