Frederico Mariath Frederico Mariath was an admiral in the Imperial Brazilian Navy who participated in the Cisplatine War and some of Brazil ' s internal conflicts of the early 19th century . Major actions . Cisplatine War . Mariath was put in command of a small squadron of four vessels stationed near Colonia del Sacramento . His mission was to defend the local fortifications , in coordination with the garrison of approximately 1 , 500 men under the command of Brigadier Manuel Jorge Rodrigues . On February 26 , 1826 , an Argentine squadron under the command of William Brown ran the blockade and appeared to challenge the garrison at Colonia . The men and guns of the Brazilian vessels had been landed to reinforce the fort , and the resulting confrontation was and inconclusive cannon duel , as a ground attack by troops from the Banda Oriental failed to materialize . After repelling this initial attack , Mariath asked for assistance from Montevideo , but the commanding Vice Admiral Rodrigo Lobo refused . On the first of March Brown launched a second attack . The night assault , supported by gunboats , was repelled after a bloody combat in which the Argentine troops suffered heavy losses but succeeded in destroying two Brazilian ships . Later that year , he was put in command of a squadron consisting of the brig " Caboclo " , the corvette " Maceió " , and the frigate " Nichteroy " . He distinguished himself in the defense of the frigate " Imperatriz " on April 26 , in the battle of Ortiz Bank on 3 May , and the battle of Lara - Quilmes on 29 and 30 June . During this last battle , the massed fire of a number of Brazilian vessels succeeded in knocking the major Argentine ship the " 25 de Mayo " out of action . On 12 May in Montevideo , Admiral Rodrigo Pinto Guedes assumed command of Brazilian naval forces operating in the Rio de la Plata sector , often called the " Escuadra del Sur " ( Southern Squadron ) . He decided to adopt a more aggressive strategy and divide his fleet in three parts to accomplish it . He put Captain James Norton in command of a squadron ( the " Division Bloqueo " ) whose mission it was to definitively blockade the strategic port of Buenos Aires . Another squadron ( the Third Division ) , led by Jacinto Sena Pereira , was ordered to control the Rio Uruguay and thereby cut lines of supply and communication between the Argentines and their expeditionary forces in the Banda Oriental . Mariath was put in charge of the reserve squadron , based at Colonia del Sacramento . Battle of Juncal . Principle article : Battle of Juncal The Argentine commander Brown soon began making plans to confront the Third Division . Fighting with a smaller force , he had to devise a way to keep the Brazilian squadrons from supporting each other , as any combination of squadrons would greatly outnumber his own fleet . His solution was to build a fort on Isla Martín García , at the mouth of the Rio Uruguay , with the purpose of protecting his flank as he chased the Third Division up the river as well as preventing the Mariath Division from reinforcing the Third . Mariath made a timid attempt to bypass the fort on its less defended side , but the danger of sand banks , the existence of a mobile battery in the fort that could be moved to cover the alternate approach , as well as the advance of the Argentine fleet , resulted in retreat . Thus on February 8 , 1827 , when the Third Division began to descend the river to link up with Mariath , they found instead Brown waiting for them . In the ensuing Battle of Juncal the Brazilian fleet was completely destroyed , with only 2 of 17 vessels escaping . Although Mariath was within earshot of the cannon fire , he judged an attempt to force his way past the fortifications to be too risky . He instead engaged in an extended gun duel with the fort , an ineffectual action which was eventually disrupted by a storm . On February 9 , while the Third Division was pursued and finished off by Brown ' s squadron , the Mariath Division remained at a distance without intervening . The next day Mariath decided to retreat in the direction of Colonia del Sacramento , where he arrived the next week . Civil Wars . In 1835 a rebellion broke out in the town of Cabanagem , Pará . The rebels succeeded in taking the provincial capital , Belém , in response to which the government sent a combined naval and land force . Although the government forces took the capital , the rebellion continued in the interior and the rebels eventually retook the city that August . Commander Mariath was sent as a replacement for the expedition ' s commander of naval forces , John Taylor . The navy proceeded to blockade the port , bombard rebel positions , land army troops , and conduct riverine patrols . The rebels were pressed hard and eventually abandoned the city and retreated again to the interior , where they would continue to fight until 1840 . 1835 was also the year that a republican uprising broke out in southern Brazil , in particular the state of Río Grande do Sul . This war was known as the " Ragamuffin War " . In 1838 the Imperial government named Mariath as military commander in the province of Santa Catarina , with the mission to confront the rebels . ( The revolution had extended to this province in the form of the República Catarinense . ) On November 15 , in command of a fleet of some 13 vessels carrying 33 guns and approximately 1000 men , Mariath defeated the republican forces under Giuseppe Garibaldi in the Barra de Laguna .