C&C and deployment are base views for describing software architectures. Both views typically exist of several models that highlight particular aspects of the software. From our experience, managing the dependencies between architectural models is a challenging, yet crucial task for maintaining consistency of an architectural description. In this paper, we focus on the composition of architectural models and managing dependencies between models in such a composition. We formally define four basic relations between models and a composition operator that enables integration of several C\&C models based on these relations. We elaborate on several semantic preserving properties of the composition operator, including traceability, consistency, and completeness. The relations and composition operator have been integrated in the xADL language and the AchStudio tool. We use excerpts of a distributed video-on-demand system designed with the tool as an illustrative case.