The siege of Humaitá was a military operation in which the Triple Alliance (Brazil, Argentina and Uruguay) flanked, besieged and captured the Fortress of Humaitá, a Paraguayan stronghold that was referred to as the Gibraltar of South America. It fell on 26 July 1868. It can be considered the key event of the Paraguayan War since the fortress had frustrated the allied advance into Paraguay for more than two years. However it did not surrender as the defenders escaped, most of them to fight another day. The allies were severely criticised for the time it took them to take the installation, whose strength was belittled. But they were essentially a pre-professional army fighting a long way from home against an unaccustomed defence tactic: artillery in prepared, entrenched positions firing a hail of anti-personnel shot. Further, they were battling in unprecedented terrain — most of it impassible, all of it unmapped — in the wetlands of southern Paraguay. It gave the Paraguayans, who fought with exemplary courage despite being abysmally supplied, a huge advantage. Moreover the allies, who at first had attempted to take the fortress by frontal attack from the Paraguay River, had instead suffered a catastrophic defeat; this had disorganised and demoralised their forces. Restoring their military effectiveness was a task that fell on the shoulders of the new commanding general the Marquess of Caxias. For political reasons he could not risk another disaster.
Context and importance
=== Brief recapitulation === The Paraguayan War was "the bloodiest inter-state war anywhere in the world between the end of the Napoleonic Wars in 1815 and the outbreak of the First World War in 1914", and far and away the most lethal in the history of South America. Yet it is little known outside that continent. It had three phases:
Paraguay declares war on Brazil and Argentina — countries vastly more populous than itself — invading three of their provinces. The two countries, plus Uruguay, sign the Treaty of the Triple Alliance, vowing never to lay down their arms until they have toppled Paraguay's leader Francisco Solano López. The Allies invade Paraguay, and at length capture its capital Asunción; Guerrilla warfare and the pursuit of López, who is finally killed by Brazilian cavalry after refusing to surrender. Its key event was the capture of the Fortress of Humaitá, which was the gateway to Paraguay, and had held up the allied advance for over two years.
The maps show why the fortress was the key to Paraguay. The country is landlocked, but can be accessed from the sea; one must sail up two of South America's great rivers in succession:
The River Paraná, which traverses many miles of Argentine territory. (A small portion of the Paraná is visible at the bottom of the Context map, marking the boundary between Argentina and Paraguay.) The River Paraguay, the country's principal highway, and after which it is named. As shown, Humaitá was a few miles up the river Paraguay. At first it was just a modest guardia or lookout point manned by a few soldiers. In the 1850s there had been two separate incidents in which Paraguay had been threatened by the naval flotillas of irate foreign powers, namely Brazil and the United States. It became apparent that warships, though based in the Atlantic Ocean, could steam up into Paraguay quite rapidly. Thus, the transition from sail to steam made the Paraguayan government realise that, far from being secure in the heart of South America, it was vulnerable.
Accordingly, the Paraguayans had greatly strengthened the fortress of Humaitá. Its purpose was to bar the way in to Paraguay. Commanding a hairpin bend in the river, it had a formidable reputation.
=== Brazilian frustration === For the Brazilians the fortress was doubly vexing. It blocked the river route to their province of Mato Grosso, which lay hundreds of miles further upstream, and had been occupied by Paraguay since the war began. It was by far the most convenient means of access to their territory, a land about the size of Germany. Unless they got past Humaitá there seemed little prospect of recovering it.
Attempt to take fortress by storm
Hoping for a quick result, the Allies tried to take the fortress by frontal assault from the river Paraguay. On 22 September 1866 they landed troops on the edge of the only substantial piece of firm ground, a meadow marked M on the map Terrain. To attack in that place was a rational decision in itself, for they had hit upon a weak spot, and they might well have prevailed, greatly shortening the war. But their commands were divided, they dithered and delayed, and the Paraguayans built a defensive earthwork in the nick of time. Armed with artillery firing a hail of grapeshot and canister, it destroyed the allied attack; many Argentine and Brazilian soldiers, advancing over open ground, were killed. The Paraguayans, staying behind their defences, had few losses. This was the battle of Curupayty, the allies' first major setback, and their worst defeat of the war.
=== Summary: situation in October 1866 === Thus, the allied armies, having landed in Paraguay, controlled only 9 square miles (2,330 hectares) of its territory: inhospitable wetlands. Their advance was stymied by this seemingly invincible fortress; and, as will now appear. they were thoroughly demoralised.
== Aftermath of the Battle of Curupayty == The allied advance into Paraguay came to a complete halt after the disaster of Curupayty.
Command changes in the Allied army
The defeat caused dissension among the allied commanders and no one knew what to do next. After the battle, Joaquim Marques Lisboa, the Viscount of Tamandaré and commander of the Imperial Brazilian Navy, Polidoro Jordão, commander of the 1st Brazilian Army Corps, and Venancio Flores, commander of the Uruguayan army, left their positions. Tamandaré was replaced by Joaquim José Inácio and Flores was replaced by Enrique Castro; according to historian Thomas Whigham, Uruguayan participation in the war was now reduced to a "token force only nominally Uruguayan in composition". The question of who should lead the Imperial forces remained however. In Brazil, emperor Pedro II was determined to continue the war despite Curupayty; the new cabinet, headed by prime minister Zacarias de Góis e Vasconcelos, of the Progressive League, which rose to power seven weeks before the battle, was tasked with continuing the war. The emperor then nominated an experienced and prestigious general to lead the Imperial forces in Paraguay: Luís Alves de Lima e Silva, then Marquess of Caxias, by a decree on 10 October 1866. The decree did not give Caxias command of the Brazilian navy; thus on paper it did not unify command of the Brazilian land and naval forces; despite this, the navy also fell under Caxias' command, and would no longer operate separately as it had done since the start of the war. There was a concern on the part of the Brazilian government not to leave the navy under Argentine president Bartolomé Mitre's command. Caxias took his first steps by creating the 3rd Army Corps in Rio Grande do Sul already on 18 October 1866, while still in Rio de Janeiro. He departed aboard the steamer Arinos on 29 October 1866, stopping at Montevideo on 2 November, Buenos Aires on 6 November, Rosario on 9 November and Corrientes on 14 November, finally reaching the allied camp in Tuyutí on 18 November. Upon his arrival, he issued his Order of the Day No.1, in which he stated to the troops that "if I didn't already know you, I would recommend you valour; but in the countless battles that have taken place to date, you have given ample proof of this military virtue"; the next day he assumed unified command of the 1st and 2nd Brazilian Army Corps.
Epidemics and overall state of the army
At that point several diseases had spread in the battlefield, but a new cholera outbreak proved worst, killing or incapacitating thousands of soldiers; the cholera epidemic became so serious that the Allied commanders tried to disguise it from both the Paraguayans and the civilian population in their respective countries, even prohibiting the use of the word "cholera" in official communications. By March 1867 the epidemic had spread to Buenos Aires and Montevideo. Less than a year later, on 2 January 1868, the illness was to kill Argentine vice-president Marcos Paz. The military camps did not follow basic hygiene practices and were filthy and disorganised. The soldiers often drank contaminated water, which they got by excavacating the nearby sandbanks; the water was contaminated by dead bodies that were frequently buried near the water sources. In order to cool a demijohn of water, the soldiers would dig a hole in the ground and bury it. Dionísio Cerqueira, a Brazilian soldier, later recalled, after having ordered a hole to be dug in his tent, that "as soon as the comrade had reached the bottom, we felt the characteristic smell of death. One more hoe hit and a rotten skull appeared. He plugged the hole and dug another one ahead". The sanitary conditions were not the only issue, for the organization and morale of the allied army were also abysmal. Referring to the state of the 1st and 2nd Brazilian Army Corps, Caxias later stated that "they seemed to belong to two different nations", as each had their own administration, accounting, payment and promotion criteria. This was also a problem in other units, especially the corps of Voluntários da Pátria (patriot volunteers). Another issue was the general lack of materiel: the cavalry was short of horses and those it had were poorly fed; the 2nd Army Corps, for example, was completely dismounted; many soldiers had traded their uniforms and walked half-naked or barefoot; the Minié rifles used by the infantry needed a ramrod to function, many of which had been damaged; the artillery lacked heavy calibre guns, something that some observers pointed out as one of the causes for the allied defeat at Curupayty; there were also no ox carts or oxen to transport goods and troops.
Federalist rebellions in Argentina
Ever since the signing of the Treaty of the Triple Alliance the commander-in-chief of all the allied forces had been Argentine president Bartolomé Mitre. After Curupayty, Mitre's prestige fell and growing 'federalist' rebellions in Argentina, headed by armed bands called montoneras, forced him to pay less attention to the war against Paraguay; this also meant that an increasing number of Argentine soldiers had to be diverted from the war to quell the rebellions in the Argentine interior, the most notable of which was led by Felipe Varela, a federalist and staunch opponent of Mitre, Brazil and the war against Paraguay. The political implications are described further below. For the Argentine federalists, Brazil was an enemy ever since its role in defeating Juan Manuel de Rosas during the Platine War fifteen years earlier.
==== Suppression ==== In November 1866, 1,000 Argentine soldiers left the allied army and marched to Buenos Aires in order to join troops being raised there to put down the rebels; Mitre appointed general Wenceslao Paunero to command this army, but its effectiveness was limited and the rebellion continued; on 24 January 1867, 1,100 more Argentine soldiers were detached from the Allied army and sent back to Argentina in order to join Paunero's army; then, the Argentine president himself embarked on a steamer on 9 February 1867, heading back to Argentina with another 3,600 soldiers and leaving only four thousand Argentine troops in Paraguay under the command of general Gelly y Obes. Command of the allied army now de facto rested in Caxias' hands, who assumed it provisionally after Mitre's departure; such a reduced number of Argentine soldiers left in the front also meant the allied army strength now depended mostly on Brazil. By April the rebellion was defeated; the rebels had received considerable aid from Chile, but could not resist the government force sent against them. Mitre returned to Paraguay in July 1867, technically reassuming command of the Allied army, though Caxias continued to exercise extensive authority.
== The great reforms == The precarious state of the troops made a deep impression on Caxias, who concluded that serious measures were needed to make the army operable and continue the campaign. The marquess later stated, after his return to Brazil, that "it was therefore necessary to call in everything, carrying out a new reorganisation and, for all of that, time was indispensable". Caxias then set out to reorganise the army, step by step, gradually improving its morale, discipline and hygiene. He took several months to reorganise and stabilise the front before deciding to resume allied actions; this made him a subject of mockery and criticism in the Brazilian press, which did not understand the issues surrounding the theatre of war.
Sanitation reforms
Caxias' first measures upon assuming command applied to hospitals, ambulances, uniforms, food and transportation. He started to reorganise the Brazilian Army's depots in Argentina and Uruguay and the health service since his departure from Brazil. The Brazilians had eleven hospitals in the region, four of which were in Paraguayan territory and all of which were overwhelmed by a large number of patients. The allied army was in complete disarray. According to Francisco Doratioto, a third of the initial Brazilian force that had crossed the Paraná River into Paraguay was either sick or wounded by the time of Caxias' arrival, despite having received reinforcements. A medical commission led by Francisco Pinheiro Guimarães, a physician and colonel of Voluntários da Pátria who had already dealt with epidemics in Brazil, was nominated by Caxias to inspect the hospitals. Guimarães isolated the cholera patients and instituted strict sanitation standards. Caxias himself was meticulous in his habits, only drinking mineral water brought to him from Rio de Janeiro and ordering his quarters to be cleaned daily. One of the goals of the commission was to inspect the hospitals to search for soldiers that were no longer sick and were overstaying with the doctors' connivance; fifteen days after the commission's creation, some twenty to twenty-five hundred soldiers were sent back to Tuyutí for active duty. In order to deal with the precarious state of the camps, Caxias also convened all division and brigade commanders for a meeting in which it was decided to create a Field Police Inspectorate. This unit would be responsible for inspecting whether the officers were following the organisation and sanitation norms or not. The police inspectors' duties required them to be zealous for the camps' safety and order; for example, they included "not allowing games, gatherings, or disorder, and to patrol areas, especially the sutlers' districts'; and "list all existing female camp followers and make them rush to the hospitals as soon as the battle begins". According to Aureliano Moura, this unit was the precurssor of what would later be the Brazilian Army's Police. The marquess himself adopted the custom of making frequent morning visits to the brigades; in these visits he inspected the camps and the soldiers, paying close attention to their armament, uniforms and training. Officers were often punished for sloppiness with the smallest details; some were even arrested.
Army reorganisation
Parallel to the sanitation improvements, the marquess also reorganised the army. Caxias began by making changes to the army's administrative structure on 22 November by Order of the Day No. 2, merging several administrative divisions and creating others. He extinguished the post of chief of staff in the 1st and 2nd army corps while keeping it in his headquarters, along with two assistants, three engineers, four aides-de-camp, some officers and amanuenses. The next day, by Order No. 3, he started to reorganise the troops. The units of Voluntários da Pátria were a great problem, for they were not standardised, with a varying number of companies and soldiers in each unit; on 20 December, they were restructured, with each one being assigned six companies. In addition, Caxias was also concerned with the tactics and procedures adopted by the troops in battle; he banned the use of any occupation badges in combat and reconnaissance missions, ordering the officers' kepi to be covered with a white tissue, similar to what the soldiers used; this demonstrated his willingness to set aside the old aristocratic pageantry if it interfered with the war. During his routine visits, the marquess noticed that some officers were not following the battle formations provided for in the military regulations in effect at the time, especially the formation of squares against cavalry; Order of the Day No. 5 had determined that whenever the infantry formed squares, it should do so in four rows. Up until that point, new recruits were immediately handed guns and sent to battle, which could endanger the entire Allied army; to tackle this issue, from 7 December onwards all new recruits were given a fifteen day training on battle maneuvers and marching before being handed guns.
=== Weapons and provisions === The materiel deficiency was also remedied. The marquess convinced the imperial court in Rio de Janeiro to buy five thousand modern breech-loading Roberts and two thousand Spencer repeating rifles from the United States. In order to teach the soldiers how to use the new breech-loading guns, Caxias ordered the 1st Army Corps to select 25 men who would be taught how to use them and then spread the knowledge to the rest of the troops. An intense movement of provisions took place, with horses and mules being bought to be used in combat and in the transport of goods; the animals began to be fed alfalfa and corn, proper food that prevented them from falling ill.
=== Results === Caxias took fourteen months to implement these measures. The results of his efforts were notable. The traveller Sir Richard Burton visited a Brazilian camp near Humaitá in August 1868 and was impressed by its hygienic cleanliness and how well the soldiers were sheltered, clothed and fed. "Before he took charge, the Brazilian army was in the worst possible condition; now it can compare favourably as regards the appliances of civilization with the most civilized".
Strategic decision: take Humaitá by siege
The plan that was to lead to the capture of Humaitá was as follows. Instead of attacking it frontally, it was to be broadly encircled from the rear and taken by siege. This required two operations, military and naval. Allied troops, starting from their existing point of concentration — their base camp near the mouth of the river Paraguay — were to effect a flanking march well to the landward side of the fortress, giving its outer defences a wide berth, then marching to rejoin the river wherever it was convenient to do so. Thus the fortress would be cut off by land. But, though isolated by land, of course the Paraguayans would have continued to resupply the fortress by river, so it was necessary to cut it off by water too. Therefore the plan called for armoured Brazilian gunboats to force their way past Humaitá's batteries and deny the river to Paraguayan vessels. As explained in the article Passage of Humaitá, this was much easier said that done. The plan had been proposed by Mitre and readily agreed by Caxias. (Long after the war, though, partisan Brazilian and Argentine journalists sought to belittle Mitre or Caxias and give sole credit to the other man.) When this plan was conceived the allies did not know where the river could be rejoined, since the local topography (carrizal, see below) makes this impossible in most places. Indeed López and his entourage came to believe the crucial information (that the river could be rejoined at a place called Tayí), and even the plan itself, was given to Caxias by a small group of Paraguayan defectors, including López's two brothers, Benigno and Venancio, the U.S. envoy to Paraguay being another one of the alleged conspirators. Implementation of the plan was nearly obstructed by the Brazilian navy, which refused to take orders from Mitre. Even after Caxias assumed supreme command they were very reluctant to proceed until forced into a corner, behaving heroically, though, when it came to the point. The map shows the simple concept. In practice there were formidable difficulties to overcome.
== Difficulties facing the Allies == Some foreign observers bitterly criticised the allies for the slowness with which they captured the fortress. It was even implied that corrupt motives might have to do with it. In recent times some conspiracy theorists have reasoned that it was done deliberately as part of a Final Solution to exterminate the Paraguayan race. Even Caxias himself, before he was given sole responsibility, grumbled that Mitre was in no hurry to get on with the war because Argentina was getting rich from it. The serious practical difficulties faced by the allies — who were operating without the benefit of hindsight — should therefore be described.
Logistics
By water
Brazilian troops, artillery, ammunition and stores had to be brought to the vicinity of Humaitá from Rio de Janeiro by steamship: a 1,500 nautical mile (2,778 km) journey down the Atlantic ocean and up again through the rivers Plate, Paraná and Paraguay that took about a fortnight. Thus ocean-going ships had to steam up the Paraná river, where they risked running aground on its frequent sandbars. The alternative, the overland route from Brazil to Paraguay was so bad that it was attempted only once, with disastrous results. Cavalry horses and draught animals died from eating "a poisonous herb called 'mio-mio', which abounds in the South of Paraguay, and which only animals reared in the district have the instinct to avoid". Hence fodder had to be imported from downriver Buenos Aires or Rosario, its price rising to £8 gold per ton. According to Richard Burton, who visited the scene, "It was terribly wasted by exposure to wind and weather, and in places I have seen it used to bridge swamps. This unexpected obstacle added prodigiously to the difficulties and expenses of the invader".
==== Terrestrial ==== The sea and river journey, though long, could be said to be the easy part. Cargoes were landed at Paso de Patria or Itapirú in southern Paraguay and had to be taken to their final destinations by mule cart. Convoys left once every two days and threaded their way through the marshlands.
By the time the allies had encircled the fortress, rejoining the river at Tayi, the route was many miles long. Those who went on it were liable to be ambushed and harassed by Paraguayan forces.
When eventually the Brazilian armoured gunboats did dash past Humaitá and remake contact with the encircling land force they had to be resupplied via this tenuous route. According to George Thompson The Allies had to transport overland to Tayi all supplies and ammunition for their ironclads. They had to pay £2 10s for the transport of a 150-pounder shot, and £33 [say, $5,000 today] for the carriage of a ton of coal. Hence this vital line of communication — it was 70 km long — might conceivably have been cut at any time if the Paraguayans had been bold and fortunate.
=== Hydrology and geology === To appreciate the wetlands terrain of southern Paraguay — where the allies were bogged down in an area of only a few square miles — it helps to understand some peculiarities of this portion of the river, called the Lower Paraguay. The Lower Paraguay has a channel that is about 2,000 feet (600 metres) wide on average; it has a meandering pattern with an irregular and complex water regime. Its hydraulic gradient (mean slope) is very small (2 cm/km). When the water is high it cannot discharge into the Paraná fast enough: it backs up and causes extensive flooding. Not far above Humaitá it receives an enormous streamload of sediment, a mud brought from the slopes of the Andes by a tributary, the Bermejo River. Thus, the Lower Paraguay is characterised by sediment erosion in the main channel and deposition in its floodplain channels. Although its left (eastern) bank is elevated, both banks are overflowed during the winter floods, as shown in the photographs from space, forming "meander scroll remnants, shallow lakes, ponds, marshes and long and narrow scroll-swamps"; the floodplain is poorly drained. The local topography is continually changing, differing in summer and winter, and even from year to year.
=== Terrain === Once the Paraguayans had denied access to the meadow M at Curupayty, there were few pieces of firm ground upon which the allied troops could manoeuvre. Most of the surrounding terrain was almost impassible, and consisted of the following features; they were described by George Thompson, chief engineer of the Paraguayan army.
Carrizal. Extending from the river bank and up to three miles inland, it was land intersected by deep lagoons and deep mud, "and between the lagoons either an impassable jungle or long intertwined grass three yards high, equally impenetrable. When the river is high, the whole 'carrizal', with very few small exceptions, is under water, and when the river is low, and the mud has had time to dry, paths may be made between the lagoons".
Esteros. Basically lagoons choked with stiff, gigantic aquatic plants, they surrounded the Paraguayan positions and formed their principal defence. "The water of these 'esteros'... is full of a rush which grows from 5 to 9 feet above the level of the water. The water in all standing ponds, is full of this rush..." These plants, called pirí, were triangular in section and grew perfectly straight.These rushes grow about two inches apart only, and are consequently almost impassable in themselves. The bottom they grow on is always a very deep mud, and the water over this mud is from 3 to 6 feet deep. The 'esteros' are consequently impassable excepting at the passes, which are places where the rushes have been torn out by the roots, and sand gradually substituted for the mud at the bottom. In these passes, as in the rest of the 'esteros', the depth of water to be waded through is from 3 to 6 feet. In some places, one or even two or three persons, on very strong horses, can pass through the rushes; but, after one horse has passed, the mud is very much worse on account of the holes made by the first horse's feet. The Chaco. On the opposite shore of the river began the Gran Chaco, a region so inhospitable it was never conquered by the Spanish Empire. Claimed by both Argentina and Paraguay, it was still uninhabited, except by the feared Toba people and other indigenous. The coastal region was almost impassible. Eventually, pressure of war obliged both sides to make quite extensive forays there; see below.
