After being defeated in the battles of the Pyrenees, Marshal Soult spent most of August re-building and re-organizing his army. By late August he was able to field a force of 45,000 men divided into nine infantry divisions. San Sebastian had still not fallen and militarily it made sense to leave it to its fate, however politically Napoleon would not be pleased if he did so. On 31 August he attacked with his army across the Bidassoa River in the vicinity of San Marcial and Vera. The attacks failed and San Sebastian eventually fell.
My questions is: what was the objectives of these attacks? Oman says in Volume 7 page 37, that Soult felt honor bound to relieve the garrison. But what does that mean? Pull the garrison out and abandon the city? Throw supplies into the city?
According to the following works, Soult was tasked with relieving both San Sebastian and Pamplona and retaining them. He was to keep a foothold in Spain and feed his army with supplies obtained there and not from France.
Wellington and the Siege of San Sebastian 1813. Bruce Collins. Pen & Sword 2017.
Wellington’s Peninsular War: Battles and Battlefields. Julian Paget. Pen & Sword 2005.
Wellington’s Two-Front War. Peninsular Campaigns at Home and Abroad 1808-1814. Joshua Moon. University of Oklahoma Press 2012.
Good question - I don't know the answer, although it is hard to imagine that he intended to abandon the town. If Soult had been that successful he would probably have hoped to defeat the whole allied army piecemeal as it was strung out on a long front with relatively poor lateral communications, so he might have been imagining an sustained advance into northern Spain rather than a two-steps-forward-one-step-back campaign. But I don't have any evidence for this either way.
I can't offer anything useful in response to your question, but it does strike me how rapidly the French were able to pull themselves together despite considerable batterings - Clausel after Salamanca, post Vittoria, and post Pyrenees. What was the key, I wonder?