Juan Lavalle, an Argentine general, capitalized on a period of turmoil in Buenos Aires to oust Governor Manuel Dorrego. The political landscape of Argentina at the time was fraught with tensions between the federalists, who favored regional autonomy led by Dorrego, and the Unitarians, who sought a centralized government. This ideological clash played a central role in the events that unfolded, as various factions competed for influence and power resulting in heightened military engagements.

On December 1, Lavalle took decisive action, leading his troops in a military coup against Dorrego. The coup was motivated not only by a desire for political power but also by a belief among Unitarians that the federalist policies of Dorrego were detrimental to the nation’s progress. The overthrow initiated a significant conflict known as the Decembrist revolution, which would bring further strife to an already divided Argentina.

Following the coup, Lavalle sought to establish control over Buenos Aires and implement Unitarian principles, yet his rule faced immediate resistance from Dorrego's supporters. This act set off a violent confrontation characterized by a series of battles and political machinations between the two factions, further entrenching the divisions within Argentine society and politics. The confrontation would have lasting implications, as it paved the way for future conflicts and the eventual rise of authoritarian regimes on both sides of the political spectrum.