Siege of Humaitá The Siege of Humaitá was a naval battle and later siege which occurred at the fortress of Humaitá , on the Paraguay River beginning on February 19 , 1868 , as a part of the Paraguayan War , and ending on July 25 , 1868 . It is also the name of a picture painted by Victor Meirelles in 1868 , depicting this event . History . On August 1 , 1867 the Argentine general Bartolomé Mitre commanded the Brazilian imperial fleet to secure a passage through Curupaiti and Humaitá . On August 15 , two divisions of five battleships passed without incident at Curupaiti , but artillery fire forced them to stop at Humaitá . This news caused conflict in the Allied high command . The Brazilian commanders determined that attacking the fortress from the river would be futile , and withdrew their fleet pending a land - based attack which began on August 18 . From Tuiu - Cuê the allies headed north and took the villages of São Solano , Vila do Pilar and Tayi , and finally laid siege to Humaitá itself , isolating it from Asunción . In February 1868 Commander Joaquim José Inácio de Barros again ordered the fleet to cross the river by Humaitá , which was done on the 19th . There were few casualties and minimal damage to any of the ships . This was done four more times until the fortress fell on July 25 of that year . Impasse . The Curupayty step was a success for the Allies , especially for Mitre , who promoted a new and immediate movement to overcome the defenses of the fortress Humaitd . From a naval perspective , Paraguay ' s position was stronger than Battle of Curupayty and Caxias as Inacio both objected again . The Brazilian commanders considered extremely risky operation for fear of batteries and unnecessary Paraguayan judge that the flanking and surrounding land would be sufficient from the time the Paraguayan fleet had been seriously diminished after the Battle of Riachuelo , adding that damage to the fleet , albeit minimal , to close the deal prevented , that the passage was closed Humaitd and narrow , which crossed the chains that would leave the fleet exposed long enough to be destroyed and that the solution was to flank and a new site . Mitre meanwhile claimed that the armor of ironclads and monitors imperial ( between 3 " and 4 " ) would be invulnerable to higher Paraguayan guns , which he saw demonstrated in the passage of Curupayty : barely projectiles produced depressions in the shield , reached were breaking bolts and drill some chimneys and weak parts of the armor , as happened to Tamandaré . Regarding the small steamers survivors felt that would be enough for the enemy would cater the fortifications and moved men and supplies between positions , which would also be shown soon . Moreover , the chain line was as vulnerable as the rafts that held and a new flanking further delay than Curupayty and cripple the squadron and operations for years . The Brazilian controls their government again appealed , but in December the Argentine vice president Marcos Paz fell ill victim of the cholera epidemic that ravaged the city of Buenos Aires and Mitre had to return to take over the presidency . Paz ' s death on January 2 , 1868 he had to leave the command of the allied forces permanently . Commanding Caxias , operations are concentrated in the operation of siege , while the fleet remained divided , some in their colony against a division anchored Curuzú and beyond Curupayty , half mile downstream Humaitd in dangerous situation between the two fortifications and must use for their communications and supplies precarious path open in the Chaco . The division maintained its position in two lines forming the vanguard composed of the Silvado , Cabral , Lima Barros and Barroso and giving Curupayty against the Tamandaré , Colombo , Brazil , Herval and Mariz e Barros . They completed the flat armored training Cuevas , Lindóia and Riachuelo . Francisco Solano Lopez made good use of the delay . Taking advantage of the nights during the months after Humaitd gradually evacuated from the besieged troops in Curupayty and most of the guns ( leaving only 22 pieces ) , despite what the strong Curupayty finally fall only on March 23 , 1868 once forced the passage of Humaitd , confirming also the view of Mitre wait fall for terrestrial site was not an option . Humaitá . Among Curupayty and Humaitd , the river Paraguay effected several curves . In facing the fortress , in a canyon 8000 meters were built casemate batteries to 6 m above the river . The older core of the device , batteries were London ( 16 pieces of heavy gauge ) battery and Chains ( 18 guns ) . To right and left stretched Amboró batteries ( 10 guns ) , Shell ( 14 ) , Tacna and Eighth ( 11 ) Coal ( 12 ) , Umbú ( 11 ) Command ( 5 ) Humaitd ( 2 ) Arsenal ( 1 ) and Coimbra ( 3 ) . To these 114 guns could add their shots in the curve some of the batteries of the device facing the plain , increasing the number to over 150 pieces of various calibres , they could converge to a maximum of 130 missiles at one point . Humaitd commanded Colonel Paulino Alen , supported by the artillery officers Colonel Francisco J . Commanders Pedro Martinez and Gill , Remigio Cabral and Pedro Hermosa , who would be directly responsible for the batteries . The river passage describing a curve there especially closed and leaning against the Paraguayan , was also defended by several lines of torpedoes or " infernal machines " and three chains of inch and a half thick , held for ten barges . Finally , a stockade step further narrowed . Battle . At midnight the division began its advance Carvalho . In Curupayty , Paraguayans detected the movement of the enemy squad Humaita direction and launched rockets notice . Humaitd advocates immediately began to light great bonfires on the two banks of the river to help aim their artillery and ironclads barely penetrated the channel of the river opposite the fort , they were met by heavy fire from their cannons in combination with artillery placed on the Chaco . Without further incident that some strandings that disrupted the march and break out that united Alagoas and Bahia with this subsequent drift downstream , at 3 in the morning five ships of the division had crossed over scarce suffering damage . A few hours later the squadron faced Timbo Fort upstream of Humaitd , getting damage your batteries ( 12 pieces of 68 and 32 ) , but suffering some damage , minimal in the Rio Grande ( 6 hits in his helmet ) , important in the Tamandaré and To . The Alagoas , led by Antônio Cordovil Maurity , was ordered to withdraw from the step and join the rest of the squad , but while the rest of the division went on , persisted in the attempt and after three failed attempts managed to cross slowly but held under the concentrated fire of the enemy ' s batteries , with nearly 200 impacts in the superstructure but without suffering major damage . He also only Timbo position and faced their batteries , though diminished in their capacity to cause damage reached . The Alagoas had been most damaged ship in the operation and " had a square meter of his helmet healthy " . After breaking below the Fort of Laurel , at 10 : 30 Tayi reached , where they met the Alagoas and the three vessels were damaged embicados . Carvalho continued with the remaining to Asuncion ( February 24 ) in a futile show of force that gave rise to Francisco Solano López Humaitd evacuate the bulk of his army and artillery without being bothered by the square , passing the Chaco and up the margin the river to establish a new line of defense in Tebicuarí .