The main aim of this article is to describe the long and winding path that covers most of the nineteenth and the beginning of the twentieth centuries that led Portugal’s republican political leadership to create an army general staff. This path, which covers the period of the constitutional monarchy during the nineteenth century to the republican revolution of 1910, attempts to determine the reasons that led the leadership of the constitutional monarchy to create a different corps – the general staff – that shared only a part of the functions with the army general staff. To assess the reason for the delay in creating this corps, the political reasons given by the new republican leadership will be considered as the trigger determining the creation of a general staff that was consistent with that of other European powers, and of Germany in particular,  and that could also respond to the peculiar military needs of the new Portuguese republic.