Sending his light cavalry under Brigadier General André Briche to take Mérida and leaving four squadrons of dragoons at Albuera to watch the garrison at Badajoz, he marched with the remainder of his army to invest Olivenza.

[2] Wellington had previously advised General Pedro de La Romana, commander of the Spanish Army of Extremadura, to either destroy the fortification at Olivenza or to repair its defences and fully garrison the town; La Romana in turn had instructed Mendizabal to slight the fortress, but Mendizabal ignored this order and reinforced the garrison with four infantry battalions.

Although he had a large (4,000-strong) contingent of cavalry, deploying two battalions to escort the prisoners taken at Olivenza back to French-held Seville left him only 5,500 infantry with which to continue his campaign.

Although his siege-train had begun to arrive, the continued absence of Gazan's infantry division left him with a weakened army.

Despite these problems, Soult decided to besiege Badajoz in hopes that Wellington would send reinforcements to the Spanish fortress and thereby reduce the Allied forces facing Masséna at the Lines of Torres Vedras.