PhD thesis - Where to put description of history of applied method? I am writing my PhD thesis within the natural sciences (ecology), following the typical structure of introduction, literature review, material &amp; methods, results, discussion, conclusion. 

For some of my analyses I am using a method which was developed about 90 years ago and has become the "standard" method in my field. I'd like to outline the origin and development of that method, along with some downsides that have become obvious in the past decades (and which I am trying to overcome by extending the method). 

Is it appropriate to do so within the methods section (instead of just having a plain description of the methods I have applied)? Or would I rather include that in an extra chapter in the literature review (where I am so far rather focussing on describing the existing knowledge rather than methods)? Or even put it in the introduction?
While there's no "right" answer here, I would put this sort of discussion in the introduction/background as its own subsection. In that section, you're providing the motivation for the research, as well as any relevant information that the user needs to understand the paper. This seems to fit that definition nicely.