In 1838 Juan Pablo Duarte founded a secret society called La Trinitaria, which sought the complete independence of Santo Domingo without any foreign intervention. Ramón Matías Mella and Francisco del Rosario Sánchez, despite not being among the founding members of La Trinitaria, were decisive in the fight for independence. Duarte and they are the three Founding Fathers of the Dominican Republic.

On February 27, 1844, the Trinitarios (the members of La Trinitaria), declared the independence from Haiti. They were backed by Pedro Santana, a wealthy cattle rancher from El Seibo, who became general of the army of the nascent Republic. The Dominican Republic's first Constitution was adopted on November 6, 1844, and was modeled after the United States Constitution.