As a prelude to invasion, Ney took the Spanish fortified town of Ciudad Rodrigo after a siege lasting from 26 April to 9 July 1810. The French re-invaded Portugal with an army of around 65,000, led by Marshal Masséna, and forced Wellington back through Almeida to Busaco. At the Battle of the Côa the French drove back Robert Crauford's Light Division after which Masséna moved to attack the held British position on the heights of Bussacoa -long ridgeresulting in the Battle of Buçaco on 27 September. Suffering heavy casualties, the French failed to dislodge the Anglo-Portuguese army. Masséna outmaneuvered Wellington after the battle, who steadily fell back to the prepared positions in the Lines. Wellington manned the fortifications with "secondary troops"25,000 Portuguese militia, 8,000 Spaniards and 2,500 British marines and artillerymen—keeping his main field army of British and Portuguese regulars dispersed to meet a French assault on any point of the Lines.