The battle was disastrous for the Second Spanish Republic, with tens of thousands left dead or wounded and little effect on the advance of the Nationalists.

As a result, the Nationalist army conquered Lleida and the hydroelectric dams that provided much of the Catalan industrial areas with electricity.

[12] Meanwhile, the Francoist armies attacked the XYZ Line north of Valencia with the intention of capturing the Republican capital, instead of advancing towards Barcelona, fearing that France would enter the war in support of the ailing Republic.

[13] In response to the situation, Spanish premier Juan Negrín approved a plan by General Vicente Rojo Lluch to launch attacks against the main Francoist forces advancing towards Valencia.

[citation needed] General Fidel Davila[citation needed] The Morocco Army Corps Cuerpo del Ejército de Marruecos led by General Juan Yagüe:[3] Except for the 50th División, made up of relatively inexperienced soldiers, all other divisions were battle-hardened Legionarios, Regulares, African mercenaries from Ifni and Western Sahara, as well as Carlist and Falangist militias.

[23] For the crossing, the Republicans chose the bend of the Ebro River between Fayon and Benifallet, an area held by the 50th Division of the Nationalist Army.

[29] Then, Franco decided to send heavy reinforcements to the Ebro’s front (eight divisions, more than 140 bombers and 100 fighters) and passed the order for the dams at Tremp and Camarasa to be opened.

Furthermore, the Condor Legion and the Aviazione Legionaria started to bomb and destroy the pontoon bridges each day, although the Republican engineers managed to repair them each night.

Because of this, only 22 tanks and a handful of artillery managed to cross the Ebro River, and Republican troops began running low on supplies, ammunition and drinking water.

The terrain around the town was extremely hilly, being dominated by the Cavalls, Pandols and Fatarella mountain ranges whose hard and bold limestone rocks and scant forest cover provided little shelter against Francoist fire.

On 1 August, the XV International Brigade launched a fierce attack against Hill 481 in front of Gandesa, suffering huge casualties; nevertheless, the Republican assault had failed due to the Nationalist air and artillery superiority and Modesto ordered the Army of the Ebro to go on the defensive.

[40] The key to the battle was Nationalist air superiority, provided by the Italian Aviazione Legionaria and German Condor Legion squadrons that flew under the Aviación Nacional markings.

[36] The Nationalists used their bombers to cut the pontoon bridges on the Ebro, and as a flying artillery to smash the Republican positions in the sierras, and to destroy their supply lines: "Republican communications were bombed to oblivion and, as so many international brigader memoirs testify, their troops were blasted off the bare and rocky hillsides by the sheer force of the incendiary materiel launched.

[36] On 11 August the Nationalists led by Camilo Alonso Vega launched an attack against the Pandols Range held by the Lister's 11th Division.

[43] Then Franco decided to send Garcia Valiño's Maestrazgo Corps to the front and on 31 August the Nationalists launched an attack against the Cavalls Range in order to advance towards Corbera.

Then Yagüe's forces broke the Republican lines, but Modesto sealed the breach with the 35th Division and ordered their troops to hold on: "Not a single position must be lost.

[46] On 30 October the troops of the Garcia Valiño's Army Corps of the Maestrazgo, led by Mohammed el Mizzian, attacked the heights of the Cavalls Range, supported by 175 guns and 100 aircraft.

[54] Antony Beevor has argued that Negrín's "active war policy" of attacking, rather than adopting strong defences and hoping for a wider European conflict or harrying the Nationalist forces, had been driven primarily by the Communist Party of Spain's desire for propaganda victories and that at the Battle of the Ebro, the policy destroyed the Republican army for no great purpose.

However, the Munich Agreement removed any hope of aid from the Western democracies and turned the political victory into a resounding military defeat.