In this paper. we consider the rolling problem (R) without spinning nor slipping of a smooth connected oriented complete Riemannian manifold (M, g) onto a space form ((M) over cap, (g) over cap) of the same dimension n >= 2. This amounts to study an n-dimensional distribution D-R, that we call the rolling distribution, and which is defined in terms of the Levi-Civita connections del(g) and del((g) over cap). We then address the issue of the complete controllability of the control system associated to D-R. The key remark is that the state space Q carries the structure of a principal bundle compatible with D-R. It implies that the orbits obtained by rolling along loops of (M, g) become Lie subgroups of the structure group of pi(Q,M). Moreover...