Between 1816 and 1820, Brazil, Portugal and the United Kingdom defeated the troops led by José Gervasio Artigas and occupied the so-called Eastern Strip (present Uruguay).
José Antonio Lavalleja had also taken part in those battles against the Portuguese and, once exiled in Buenos Aires, he organized a new military expedition to expel the Brazilian for good. Thus, the porteño army forces called ganaderos and saladeristas (from Buenos Aires) offered their unconditional support and their representative, Juan Manuel de Rosas, provided the necessary funds for the operation to succeed.
On April 15, 1825, the forces led by Lavalleja embarked at the District of San Isidro in Buenos Aires and crossed the Uruguay River during the night to finally land sluggishly at dawn. On April 19, 33 eastern men arrived at Agraciada Beach and began the arduous labor of independence. Many of these men were Paraguayan and Argentinian islanders.
On May 20, they took Montevideo and a provisional government was settled there to achieve the same aim the armed uprising had managed but this time in the political field. On August 25, this new government declared the independence from the Banca Oriental de Brasil and the incorporation of Uruguay to the United Provinces of the Río de la Plata.
The town of Treinta y Tres was created in 1853 during the administration of Juan Francisco Giró. Even today, its dwellers keep the spirit of those year.