he nor his government had any role in Flores' rebellion, and that Argentina would remain neutral. On 26 December, the Paraguayans invaded the Brazilian province of Mato Grosso, laying waste to towns and the countryside. As the situation deteriorated, the Brazilian government mobilized army units from other regions of the Empire. On 1 January 1865, one brigade (composed of two infantry battalions and one artillery battalion) with 1,700 men from the Brazilian province of Rio de Janeiro disembarked and occupied the Uruguayan town of Fray Bentos. Paranhos, along with Tamandaré, met Flores in Fray Bentos and decided to launch a combined attack against Montevideo. It was apparent that the Paraguayans would take too long to reach Uruguay and no help would come from Urquiza and his Argentine Federalists. Increasingly isolated, Aguirre hoped that the foreign powers could intervene, but when, on 11 January, he asked the diplomatic corps in Montevideo whether they would provide military assistance to him and his government, none responded positively. João Propício Mena Barreto sailed from Fray Bentos on 14 January with the Brazilian infantry, bound for a landing near the mouth of the Santa Lucía River near Montevideo. On the way, he occupied the Uruguayan town of Colonia del Sacramento, garrisoning it with 50 soldiers. The cavalry and artillery were placed under Osório and went overland. They met João Propício Mena Barreto and the infantry at their landing place. From there, the reunited Army of the South marched on Montevideo. On 31 January, Brazil and the Colorados besieged the Uruguayan capital. In the meantime, on 19 January, Paranhos attempted to clarify the nature of the Brazilian operations against the Blancos. He issued notes to the foreign diplomatic corps in Buenos Aires declaring that a state of war existed between Brazil and Uruguay. Until then, there had been no formal declaration of war, and the Empire's military operations in Uruguay since August 1864 had been mere "reprisals"—the vague term used by Brazilian diplomacy since the ultimatum. Armistice In an attempt to divert the attention of Brazil from the siege of the capital, the Blanco government ordered the "Vanguard Army of the Republic of Uruguay", composed of 1,500 men under General Basilio Muñoz, to invade Brazilian soil. On 27 January 1865, Muñoz crossed the border and exchanged fire with 500 cavalrymen from Brazil's National Guard units. The Brazilians retreated to the town of Jaguarão, where they were