  The aim of this paper is to interpret the Grothendieck construction in the
monoidal world. That is to say, we restrict the equivalence between fibred
categories and pseudo functors to the case of categories having only a single
object. On other way of expressing this is to say that we are given a monoid
homomorphism. Though only a specialisation, we discover many pleasant results
and interpret many things in a new light. We also touch upon the case of finite
groups as an example.
