While Wellington faced Marshal André Masséna's Army of Portugal in the north, his lieutenant Beresford attempted to capture French-held Badajoz in the south. Beresford invested the city in April but Philippon's garrison successfully fended off his attacks. The siege was briefly lifted while the Battle of Albuera was fought on 16 May. Though both sides suffered horrific casualties, Beresford emerged the victor and Soult retreated to the east. Wellington brought reinforcements from the north and resumed the siege, but progress was slow in the face of spirited French resistance. Meanwhile, Masséna's replacement Marmont brought large forces south to join Soult. The British commander lifted the siege after being menaced by the numerically superior French army led by Soult and Marmont.
Hoping to assist Marshal André Masséna's invasion of Portugal, Emperor Napoleon ordered Marshal Nicolas Soult to act. Accordingly, Soult set out in January 1811 with 13,500 foot soldiers, 4,000 horse, and 2,000 gunners and sappers to besiege Badajoz. In a preliminary operation, Soult captured Olivenza in a two-week siege that ended on 23 January. The French seized 4,161 Spanish prisoners and 18 guns for an admitted loss of only 15 killed and 40 wounded. On 27 January, Soult's army invested Badajoz. Despite the interference of a 15,000-man Spanish relief army, the results were all the French could have hoped for. On 19 February, Soult sent Marshal Édouard Mortier to deal with the Spanish army. Mortier won a crushing victory in the Battle of the Gebora. The Spanish lost 850 killed and wounded plus 4,000 men, 17 guns, and 6 colors captured. French casualties only numbered 403. Turning to the siege, Soult forced a surrender on 11 March. The 4,340-man Spanish garrison plus 2,000 fugitives from the Battle of the Gebora lost about 1,000 killed and wounded while the rest became prisoners. The French sustained 1,900 casualties in the siege.
At about this time Soult received intelligence that Spanish General Francisco Ballesteros was menacing Seville and Marshal Claude Perrin Victor had been defeated by General Thomas Graham at the Battle of Barrosa. Leaving Mortier and 11,000 soldiers to hold Badajoz and environs, Soult hurried away with the remainder to deal with the twin threats. Meanwhile, Mortier besieged and captured Campo Maior on 21 March. As his subordinate General of Division Victor de Fay de Latour-Maubourg convoyed the captured cannon back to Badajoz, he was surprised by the cavalry vanguard of William Carr Beresford's approaching Anglo-Portuguese corps. In the Battle of Campo Maior on 25 March, the British 13th Light Dragoons scored an initial success, then lost all control as they galloped after the defeated French dragoons. In the confusion, Latour-Maubourg kept his head and, with the help of Mortier, managed to save the artillery convoy except for one artillery piece. Nevertheless, the appearance of Beresford and 18,000 Allied troops threw the French onto the defensive.
A field marshal in the service of Portugal, Beresford had available the 2nd Division, the 4th Division, Major General John Hamilton's Portuguese Division, and General Robert Ballard Long's cavalry. If he could have invested Badajoz at the end of March, Beresford might have found the defenses of the fortress in poor shape. However, problems arose to delay the operation until the French effected repairs. First, the 4th Division was immobilized by a lack of shoes and had to wait for a new shipment from Lisbon. Next, ample bridging material was supposed to be available at the Portuguese fortress of Elvas, but the number of pontoons proved inadequate to span the Guadiana River. The military engineers improvised a bridge, but it was immediately washed out by a flood on 4 April. A battalion was ferried across on the 5th, and starting on 6 April, the Allied corps began slowly filing across the Guadiana on a rickety structure. Luckily, for the Allies, the French did not contest the crossing. Mortier had been recalled and his replacement Latour-Maubourg lacked his strategic insight.
Too late, Latour-Maubourg finally woke up and sent two cavalry regiments and four infantry battalions on a reconnaissance to find out what was afoot. On the night of the 6th, the French flying column gobbled up a picket of the 13th Light Dragoons. The British lost 52 horsemen captured in this misadventure. General of Brigade Michel Veilande reported that the Allies were across the Guadiana in great strength. Before withdrawing from the area, Latour-Maubourg left General of Brigade Armand Philippon with 3,000 men in Badajoz and 400 soldiers in Olivenza (Olivença). Unaware that Olivenza had such a weak garrison, the Allies laid siege to it on 9 April. The place fell on the 14th after six Portuguese 24-pound cannons blasted a breach in the walls. The same week, Beresford was joined by a Spanish force numbering 3,000 infantry and 1,000 cavalry under General Francisco Javier Castaños.