Description logics are a family of knowledge representation languages constructed for a wide area of application domains. They are based on the notion of concepts and roles, and are mainly characterized by constructors that allow complex concepts and roles to be built from atomic ones. Constructor selection depends on the application domain the representation formalism is designed for. This paper concerns a special type of DLs extended with temporal operators. After.an overview of basic description logics, original results related to the temporal extensions of DLs, precisely venus, which has been modeled with an aim to overcome problems of reasoning over conceptual schemas and queries in temporal databases are given.