This paper presents an Event-B meta-modelisation of an Event-B project restricted to its context hierarchy which introduces the functional part of a development through sets, constants, axioms and theorems. We study the proposal of a new mechanism for Event-B. It consists in allowing to instantiate in a new context an already proved theorem in a given context. We investigate the validation of the instantiation mechanism in order to prove the validity of imported theorems. We also compare the proposal with similar mechanisms available within some existing theorem provers.