In the early spring Soult, who was besieging Cadiz, received orders from Napoleon to cooperate with Massena and, although ignorant of the latter's plans, and even of his position, prepared to do so at once.

He crushed the Spanish force on the Gebora; captured Badajoz, owing to the treachery and cowardice of its commander; and was moving north, when the news reached him that Massena was falling back.

The latter's position had, indeed, become untenable.

His army was wasted by sickness; and famine threatened it, for the supplies obtainable from the country round had now been exhausted.
Wellington was, as he knew from his agents in the Portuguese government, receiving reinforcements; and would shortly be in a position to assume the offensive.
The discipline in the French army under Massena had been greatly injured by its long inactivity.

The only news he received as to Soult's movements was that he was near Badajoz; therefore, the first week in March he began his retreat, by sending off 10,000 sick and all his stores to Thomar.