Abstract
When developing a software system, its architecture must be considered so that it can be understood, updated, and improved. In general, considering the architectural artefacts is not enough. The reasons, assumptions and justifications bore in mind by the architects during the architecture design stage must be also known. Nevertheless, not all aspects analysed during the design process can be identified, especially all those alternatives that were evaluated and rejected. In the present contribution, a model to represent the rationale generated by architects during the architectural design is proposed so that it can last over time and it can be retrieved, analysed and reused whenever necessary. The model includes concepts representing architectural artefacts, reasons, assumptions, and decisions and reasoning elements status.