The Cisplatine War (1825–1828) between the Empire of Brazil and the United Provinces of the Río de la Plata over Cisplatina (present-day Uruguay), was not going well for either side.

Argentine victories on land were offset by Brazil's effective control over the Río de la Plata and the naval blockade imposed on the port of Buenos Aires.

Pedro I, the Brazilian emperor, sent colonel William Cotter back to his native Ireland to recruit Irish mercenary soldiers.

Relief, and trouble, were readily available to all the mercenaries at the local grog shops in the form of a cheap yet powerful rum, called cachaça.

Taunts of 'white slaves' when the Irish first landed escalated into individual fights, then large scale brawls, and finally, into murders by roving bands on both sides in the dark streets.

[4] Unrest grew among both the Irish and the German mercenaries due to rough treatment, non-payment of wages, general misery and rumors of going into battle soon.

[5] By the second day, it was realised that the available Brazilian troops in Rio de Janeiro were insufficient to quell the armed and drunk mobs.

The mutiny virtually destroyed two of emperor Pedro's supposed best units and ended his hopes for a land victory to augment his successful naval blockade of Argentina.

Pedro ratified the peace treaty on 28 August 1828, and the Cisplatina province became independent as Uruguay, a buffer state between Brazil and Argentina.