Following the Brazilian Declaration of Independence from Portugal in September 1822, Brazil began assembling a fleet of warships; but had difficulty finding trained sailors to man those ships.

Thomas Cochrane, who ended Spanish control of Chile with the capture of Valdivia in February 1820, was offered command of the Brazilian fleet.

Cochrane found fabrics had deteriorated so sails were frequently torn by the wind and gunpowder bags were unsafe to use without swabbing the cannon bore with sponges between shots.

Pedro I opened fire on Princesa Real at noon, in anticipation the remainder of the Brazilian squadron would engage the other three Portuguese ships.

Cochrane successfully disengaged upon recognizing the inability to obtain even localized advantage; and prevented the Portuguese crew of Real from surrendering their Brazilian ship to the enemy.

[3] When Brigadier General Inácio Luís Madeira de Melo and his Portuguese soldiers left the capital on the morning of 2 July 1823, Cochrane pursued the fleet to Portugal, managing to capture seven ships during the chase.