ABSTRACT The following paper is my analysis of the development of the Spanish Republicanism during the first third of the 20th century. I have taken as a reference the intellectual inheritance of the main republican trends of the end of the century (posibilista, federal and progresist) to study the most important changes produced within the Spanish Republicanism. I will also analyse the ideological principles of these trends themselves, as well as other factors such as the impact of the most influent European trends in Spain in this period. Afterwards I will also exhibit the evolution of Republicanism highlighting aspects like the efforts to attain stable alliances, also to try to hurdle the challenges that came with the Spanish political life in the beginning of the 20th century, brought about by the Restoration. The mentioned efforts finally had to surrender to the emergence of two main trends: the radical trend, represented by Alejandro Lerroux in 1908, and the reformist one, identified by the leading figure of Melquíades Álvarez and the Reformist Party created in 1912. These two trends got a clearer profile until the Dictatorship period of Primo de Rivera. They can be considered responsible for the political modernization that allowed the historic Republicanism to finally overcome the crisis of identity that was traditionally characterized for the lack of common projects and internal divergences. Since then and regarding the initial absence of new proposals capable of stopping the new political repression of the own Dictatorship, a new Republicanism grew, expressed through the foundation of the Alianza Republicana (“Republican Alliance”) in 1926. The new ways of political performances, together with the support of the main intellectual figures of the period, could manage attempts to bring down the Dictatorship government through military actions. Nevertheless, the most important factor was to achieve a movilization of the public opinion and being able to make the most of the only real chance they had to democratize the political system of the country. Thus reinforced by the weakness of the monarchy of Alfonso XIII, they finally attained the ultimate victory in the municipal elections of April 12th, 1931 and established the II Republic in Spain.
