The Swedish Armed Forces organize its army according to the principal of combined arms without establishing that the method of combined arms is appropriate or superior to other forms of organization. Robert Leonhard claims that Nations have been organizing their army’s according to the principal of combined arms since the Antiques. This thesis was carried out as a theory testing case study with the aim to review Robert Leonhards combined arms theory against the historical cases Lützen 1632 and River Meuse crossing 1940 by examining how the theory can explain military success on the tactical level. The analysis is based on an operationalization of Robert Leonhards combined arms theory’s principles. The result of the analysis shows that Robert Leonhards combined arms theory can say something about military success in the tactical level, but more research is needed to determine if the theory and its principles by its own can explain military success in the tactical level. While this study aids to the existing body of knowledge further studies are necessary to further validate the Swedish Armed Forces use of combined arms.