After the capture of Seville in February 1810, Mortier is ordered by Soult to invade Extremadura with his V Corps with the aim of capturing Badajoz. Forced to retreat by the arrival of a Spanish army, Mortier returns to Seville.

The Marques de La Romana now commands the Spanish army in Extremadura. After Mortier's retreat from Badajoz he sends the divisions of Ballasteros and Contreras to pursue him into the Sierra, link up with Copons y Navia who will shortly land at Ayamonte to gather dispersos, and ultimately threaten French control of the Condado de Niebla and Seville.

This chapter of the campaign begins on 15 March 1810 and ends in April 1810 with the arrival of Copons y Navia at Ayamonte. Exactly when this phase ends depends on campaign situation.

Marshal Mortier is ordered to use his V Corps and the Spanish units assigned to it to:

1. Protect Seville from all enemy threats at all costs.
2. Extend French control west of Seville towards Huelva with the aim of protecting Andalucia from incursion by sea and improving French control of the province.
3. Monitor the passes through the sierra and intercept the enemy if they attempt to move south from Extremadura into Andalucia.

Girard's division of V Corps is to remain stationed at Seville as a central reserve and to defend the city from threats, together with the assembling units of King Joseph's Spanish army.

Pepin's brigade of Gazan's division is to remain at Santa Olalla watching the high road from Extremadura toward Seville. The brigade is to report any contact with the enemy but not to risk a serious engagement, instead falling back to Ronquillo and the river crossing north of Seville.

Maransin's brigade of Gazan's division with the 8th Train Battalion will move to San Lucar and create a supply depot while supporting Beauregard's cavalry with Aremberg's 27th Chasseurs and the 6th Horse Artillery who will scout towards Niebla and report back any sighting of the enemy.

Marisy's brigade of dragoons will move to Ronquillo to maintain a link with Pepin's brigade while escorting 10th (bis) Train Battalion who will create a supply depot at Ronquillo before returning to Seville.

Pepin at Santa Olalla has a report from the scouting of Beauregarde's dragoons of significant enemy infantry to the west in the sierra, and of Spanish cavalry to the north coming down the main road towards Seville. He must now decide whether in accordance with his orders he either remains holding Santa Olalla or retreats towards Ronquillo. This is a command and experience test where the best interests of the French forces are probably for him to move his brigade back to Ronquillo. Pepin fails this test and orders his brigade to remain at Santa Olalla. Pepin also sends a request to Beauregarde to return with his dragoon brigade.

Mortier receives a report from Pepin at Santa Olalla that Spanish forces are approaching the town from both the North and the West, that there are guerilla in the hills, but that he is holding is ground. He considers whether to simply order Pepin to fall back in accordance with his original orders, or to put the security of Seville at risk by ordering a substantial force north into the hills to challenge the Spanish. This is a mental and command test of how aggressive Mortier will be, with the best interests of the French in sending a significant force north. Mortier fails the test, concerned to follow his instructions to protect the security of Seville at all costs he orders Pepin to fall back to Ronquillo in accordance with his original instructions, and orders the dragoon brigade that has been moving along the road to join him in support.

Pepin has retreated to Ronquillo in accordance with his original instructions, but with no supporting forces in sight and the Spanish continuing to press down the road Pepin needs to decide whether to attempt to maintain his position in the face of the Spanish or continue to retreat towards Seville. This is a mental test where the best interests of the French are served by Pepin attempting to hold his ground in the sierra. He passes the test and Pepin orders is brigade to hold tight at Ronquillo.

Pepin is joined by Beauregarde's brigade of dragoons, but is now faced by 4 brigades of Spanish infantry joined by cavalry and artillery. Pepin's orders, reiterated by Mortier's new instructions to Beauregarde, are not to risk a serious engagement with the enemy. However retreating in the face of such a large force will be an hazardous manoeuvre to attempt. This is a command test for Pepin to decide whether he feels able to attempt retreat, the course of action most in accord with his orders. Pepin fails the test and stands his ground around El Ronquillo to await the Spanish assault.

Mariscal de Campo Ballasteros and Mariscal de Campo Senen de Contreras are ordered to advance south through the sierra towards Seville. Establish any French presence within the mountains and if contact is established push them south. You should take advantage of any opportunity presented to gain control of Seville. Otherwise maintain contact with the French, continue to threaten to approach Seville with the aim of preventing them from moving beyond the city and maintaining patriot control of the west of Andalucia.

The division of Contreras (the brigades of Munoz and Soriano) together with the cavalry brigade of the Principe de Anglona and the artillery of the 2nd regiment is to advance down the main road from Badajoz to Seville via Monasterio towards Santa Olalla. The aim is for them to probe the road and establish any French presence on the main road. If French are encountered, Contreras is not to seek an engagement and is rather to observe and withdraw if pressed. The wagon train is to accompany them.

The division of Ballasteros (the brigades of Ramirez, Avila, Moreno, and Martinez) together with the 4th artillery regiment and the mule train are to advance into the sierra off the main road via Fregenal and manoeuvre the French out of the hills. He may engage the enemy if an advantageous opportunity arises.

Having received reports of enemy cavalry in the Condado de Niebla encountered by the local guerrilleros and of a larger force of infantry at Santa Olalla, Ballesteros considers whether to follow the original plan to probe the main road and force any French forces to retire, or to press onto the area west of Seville and secure it for the patriot forces. Either would meet the spirit of La Romana's original orders. This is a Command and Experience test where the best interest of the Spanish forces is probably to execute the attack on Santa Olalla. Ballasteros passes this test and orders his division to take the route across the Sierra to cut the French at Santa Ollala off from Seville.

Following the victory at Santa Olalla, the divisions of Ballasteros and Contreras concentrate at Santa Olalla. Having now encountered the enemy, Ballasteros considers whether to continue probing south or divert through the sierra towards Huelva. This is a Command test where the best interest of the Spanish forces is to cautiously test the French defences. Experience will dictate whether the Spanish remain concentrated or divide their forces in the face of multiple threats. Ballasteros passes the test and will stay concentrated while they probe the French positions.

After concentrating at Santa Olalla, Ballasteros will press south down the high road seeking to maintain contact with the French and test the defences of Seville, with Anglona's cavalry scouting in front. One brigade of Ballasteros' division will remain at Santa Olalla to form a reserve and probe west into the sierra to explore the route through the hills to Huelva.

• 18/3/1810: Valverde
• 20/3/1810: La Guerilla
• 26/3/1810: Santa Olalla
• 29/3/1810: El Ronquillo

The Spanish can claim a complete victory in this chapter if they capture Seville, at which point the chapter ends immediately.

The French can claim a complete victory if at the end of the chapter they control both Seville and 200 overall revenue points according to the campaign economy report.

If the Spanish control Huelva and prevent the French from control 200 overall revenue points, they can claim a partial victory.

Any other outcome is a draw.

• Esdaile, Charles Outpost of Empire (University of Oklahoma Press, Norman USA, 2012) pages 344-345
• Oman, Charles A History of the Peninsular War Volume 3 (Greenhill Books, London, 1996) pages 214-215