Passage: It was established as axiomatic in anthropological research by Franz Boas in the first few decades of the 20th century and later popularized by his students.  Boas first articulated the idea in 1887: "civilization is not something absolute, but ... is relative, and ... our ideas and conceptions are true only so far as our civilization goes". However, Boas did not coin the term.

Question: When did Boas establish his ideas about axiomatic in anthropological research?
1887