An ancient Viking went for a trip to Egypt and got the recipe, but since it was in Egyptian, something was lost in the translation!...........
Wikipedia claims that the first written record of Lutefisk comes from a King of Norway in the mid-16th century. Nordic folklore has it that Lutefisk came about when, in Ireland, St. Patrick ordered his retainers to pour lye over the dried fish on a Viking longboat, with the aim of poisoning the Vikings; but that the vikings, after soaking their alkaline fish in water and cooking it, pronounced it delicious.
You just can’t find any way to mess with people tough enough to cross the North Sea routinely in shallow-draft open boats.