Thirty-Three Orientals

Previously, a separatist movement (1822–1823) directed by various partisans of the United Provinces of the Río de la Plata (present day Argentina) had been subdued by the Brazilians.

The beef-curers had seen their regional markets impaired through competition with their neighbors at Rio Grande do Sul, who were supplied with cattle from Cisplatina.

On April 1, 1825, an advance party led by Manuel Oribe set sail from the port of San Isidro and landed at the Brazo Largo island on the Paraná river.

After nightfall, on April 18, Lavalleja and his men advanced carefully among the isles of the Paraná Delta, evading the vigil of the Brazilian flotilla.

Long afterwards, in 1877, the event would be portrayed by the painter Juan Manuel Blanes, in El Juramento de los Treinta y Tres Orientales (Oath of the Thirty-Three Orientlas), one of the images most deeply inscribed in the historical memory of Uruguayans.

Blanes often addressed historical themes in his works, and in this case achieved detailed renderings of the protagonists' faces, interviewing some survivors and taking extensive notes.

The military expedition of the Treinta y Tres proceeded to attract countryside inhabitants to the cause of freedom from the Brazilians, and made its way to Montevideo, where it arrived on May 20, 1825.

According to Jacinto Carranza, who compared extant lists for his 1946 book ¿Cuántos eran los Treinta y Tres?