Is the Monastic book called Norse actually just a copy of the book called Nofis (438 A.D. Brehon Law -Saint Patrick and three kings) and is it true to say that the book called Norse that first appeared in the 13th century is regularly mistranslated?

 It seems there might be some confusion here. The term "Norse" typically refers to the language, culture, and people of medieval Scandinavia (Norway, Sweden, Denmark, and sometimes Iceland). There isn't a well-known monastic book called "Norse" in the context you're describing.

It's possible that you're referring to a specific manuscript or document that might be associated with Norse culture or history, but without more context, it's difficult to say for certain. Additionally, the connection between a book called "Norse" and another called "Nofis" (which I couldn't find any reference to) in the context of 438 A.D. Brehon Law and Saint Patrick is unclear.

Regarding the claim about the book "Norse" being regularly mistranslated, I can't comment on it without knowing more specifics about the book in question and the translations being referenced. However, it's not uncommon for ancient texts to be subject to different interpretations and translations over time, which can sometimes lead to misunderstandings or mistranslations.