The combat of Sumbilla (1 August 1813) was a rearguard action in which two British divisions attempted to catch up with Soult’s troops retreating down the Bidassoa valley in the aftermath of their defeat at the second battle of Sorauren.
In the aftermath of the second battle of Sorauren Soult realised that he would have to retreat back into France. Two of his three ‘corps’, those of Reille and Clausel, had suffered heavily in the battle, and Soult probably didn’t believe that they could stand up to another attack. As a result he decided not to retreat up the main road up the Velate Pass pass, and instead ordered his two damaged ‘corps’ to move west towards Drouet’s undefeated forces, which had been fighting further to the west, at Beunza. Drouet would then act as a rearguard while the other two units began to retreat north over the Peurto de Arraiz, heading towards Sanesteban, at a bend in the Bidassoa valley. Once the French reached the valley they were to continue north down the river until they reached a side valley heading to the col de Echalar, on the Franco-Spanish border. They would then leave the Bidassoa and follow this side valley towards safety.
This move caught Wellington by surprise. He expected Soult to lead his main force over the Velate Pass, and perhaps even send some up the Roncesvalles route further to the east. As a result Wellington sent most of his troops along these eastern routes, leaving only Dalhousie’s 7th Division to follow the Puerto de Arraiz. Even Hill’s 2nd Division, which had fought at Beunza, was ordered to move to the Velate route. However Hill was so close to the retreating French that he was to follow them along the correct route. The only significant fighting on 31 July was thus a rearguard action between the retreating Frence and Dalhousie and Hill. In the aftermath Hill obeyed his orders, and moved off to the east, leaving only Dalhousie to cross the Puerto de Arraiz (on the night of 31 July-1 August his men camped at the top of the pass). Further east Wellington’s main column reached the Bidassoa to the east of Soult, and Byng’s brigade captured a French supply convoy at Elizondo.
By the morning of 1 August Wellington was finally convinced that the main French force was around Sanesteban. Cole’s 4th Division was ordered to advance along the north bank of the Bidassoa (as it flowed west from Elizondo towards Sanesteban), while Dalhousie was ordered to attack on the south bank after crossing the Puerto de Arraiz. Further downstream the only Allied troops in Soult’s way were two Spanish companies posted at the bridge of Yanzi (where a side road coming from the village of Yanzi crossed the river to join the main road, which ran up the eastern side of the valley).
Soult managed to escape from this trap, mainly because he realised he was still in danger, and ordered his men to move off by 2.30am, well before dawn on 1 August. Reille’s men were mixed in with the cavalry and the baggage train at the head of the column, causing a great deal of confusion. Drouet’s divisions were next in line, and Clausel formed the rearguard. Reille and Clausel were to follow the main route to Echalar, while Drouet was meant to follow a smaller route across the mountains, which left the main valley near Sumbilla. In the end Clausel would follow this route and the rest of the army the main road.
Clausel has left us the best account of this combat. He posted Vandermaesen’s division as his rearguard, posted on a hill on the north side of the river facing Sanesteban. Taupin’s division was placed in support, while Conroux was ordered to join the retreat, but found his route blocked by Drouet’s baggage. Clausel then ordered his men to leave the road and march along the slopes above it whenever possible.
On the British side Cole’s 4th Division was first to arrive, and was in contact with the French by 7am. Dalhousie’s troops arrived rather later. Cole attacked in lines of skirmishes on the hills, in an attempt to get around the French left. Both sides ended up extending their lines up the top of the ridge east of the river, with the British reaching the top first,. Vandermaesen’s troops were forced to retreat, and only rallied when they reached Taupin’s troops near Sumbilla. About an hour of skirmishing followed, before Clausel’s divisions abandoned the Bidassoa road and cut north-east across the hills towards Echalar. The British then attacked Darmagnac’s division in the valley, harassing them from the hillside above the road.
The fighting was probably never very heavy. The 7th Division never reached the front, and suffered no casualties on the day. The 4th Division only lost 48 killed and wounded (3 men killed, three officers and 42 men wounded), so the French can’t have offered much resistance, and the day was probably taken up with something of a race across the hilly ground. On the French side Vandermaesen lost six officers and Conroux one, allowing us to estimate their overall losses as around 150-160.
Further to the north the small Spanish force at the bridge of Yanzi managed to hold the front of the French column up for some time, so if Wellington had been able to commit more troops to the pursuit, or started earlier, then Soult might have suffered heavily. As it was he was able to escape reasonably intact, although the events of the combat of Echalar (2 August 1813) suggest that his army’s morale had suffered very badly.