 Brazilian independence did not meet with unanimous approval in the south . Part of the army , led by Dom Álvaro de Macedo ( later Count of Ilha da Madeira ) , entrenched itself in Montevideo and remained loyal to Portugal . The town was besieged by forces under Laguna . Following his return from the imperial capital , Marques de Sousa served under his father 's command , taking part in the siege and later fighting in the successful Battle of Las Piedras on 18 May 1823 . In early 1824 , Macedo and his men surrendered . The end of the Brazilian War of Independence came at a cost for Marques de Sousa . His father was mysteriously murdered with poison in Montevideo on 21 November 1824 , leaving him the head of his family at age 20 , as his paternal grandfather had died ( of old age ) on 22 April 1822 . He was promoted to lieutenant ( modern @-@ day first lieutenant ) on 1 December 1824 for his acts of bravery during the war . 
