Abstract
This article analyses the evolution of civil-military relations in Spain from 1923 to 2021. The research defines the role of the military organisation during two authoritarian regimes in the 20th century along with the country’s democratic transition. After a historical overview, the military change process known as Experimental Brigade 2035 is selected as a case study to determine whether its origin is civilian or military in nature. The results of the research evidence the civilian infl uence in budgetary issues and limits in performance. At the same time, the military has a certain autonomy to implement modernisation plans in the framework of assigned competences