In December Massena, having exhausted the country round, fell back to a very strong position at Santarem; and Terence withdrew his whole force, save those guarding the defiles, to the neighbourhood of Abrantes; so that he could either assist the force stationed there, should Massena retire up the Tagus; and prevent his messengers passing through the country between the river and the range of mountains, south of the Alva, by Castello Branco or Velha; posting strong parties to guard the fords of the Zezere.
So thoroughly was the service of watching the frontier line carried out, that it was not until General Foy, himself, was sent off by Massena, that Napoleon was informed of the state of things.

He was accompanied by a strong cavalry force and 4000 French infantry across the Zezere, and ravaged the country for a considerable distance.
Before such strength, Terence was obliged to fall back.

Foy was accompanied by his cavalry, until he had passed through Castello Branco; and was then able to ride, without further opposition, to Ciudad Rodrigo.
Beresford was guarding the line of the Tagus, between the mouth of the Zezere and the point occupied on the opposite bank by Wellington, sending a portion of his force up the Zezere; and these harassed the French marauding parties, extending their devastations along the line of the Mondego.
Although the Minho regiment had suffered some loss, during these operations, their ranks were kept up to the full strength without difficulty.

Great numbers of the Portuguese army deserted during the winter, owing to the hardships they endured, from want of food and the irregularity of their pay.

Many of these made for the Minho regiment, which they had learned was well fed, and received their pay with some degree of regularity, the latter circumstance being due to the fact that Terence had the good luck to capture, with one of the convoys behind Ciudad Rodrigo, a considerable sum of money intended for the pay of the garrison.