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
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