We combine the modal logic S5 with the description logic (DL) ALCQI . The resulting multi-dimensional DL S5ALCQI supports reasoning about change by allowing to express that concepts and roles change over time. It cannot, however, discriminate between changes in the past and in the future. Our main technical result is that satisfiability of S5ALCQI concepts with respect to general TBoxes (including GCIs) is decidable and 2-EXPTIME-complete. In contrast, reasoning in temporal DLs that are able to discriminate between past and future is inherently undecidable. We argue that our logic is sufficient for reasoning about temporal conceptual models with time-stamping constraints.