where the main road is so steep that a six-pounder requires not only a dozen horses but the assistance of fifty men to get it up the slope. Except in the immediate neighbourhood of Castello Branco, the country-side is almost uninhabited[156]. The whole ‘corregidoria,’ which took its name from that town, and extended from the Elga to the Zezere, had only 40,000 souls in its broad limits--it was forty miles long by thirty broad, the size of a large English county. Junot’s experiences served as a warning to his successors, and no French army during the rest of the war endeavoured to cross this corner of Portugal when advancing on Lisbon. Castello Branco was seized once or twice by a raiding force, but it was never used as the starting-point of an army making a serious attempt to advance towards the Portuguese capital. [156] The above notes on the Castello Branco country and its roads are mostly derived from Eliot’s _Defence of Portugal_. Eliot has marched all over the region; see his pages 78-81. There remains to be considered only the section of the frontier between the Douro and the Serra da Estrella, the front on which Masséna’s great blow was delivered in the autumn of 1810. It was a region which had from the earliest times been the battle-ground of the Spanish and Portuguese. Half a dozen times since the Middle Ages armies from the plains of Leon had invaded the Beira on this front. Such campaigns always began with a siege of Almeida, the sentinel-fortress pushed out in front of the mountains to face the Spanish Ciudad Rodrigo. Almeida generally fell--it is too advanced a position for safety, and (as Dumouriez remarked in his military study of Portugal) its value would have doubled if it had only been placed upon the west instead of the east bank of the Coa, close to the friendly mountains, and not on the outskirts of the perilous plain. But rare, indeed, were the occasions on which the Spaniard succeeded in piercing the broad belt of tangled upland beyond Almeida, and appearing at the gates of Coimbra or Oporto. [Illustration: CENTRAL PORTUGAL.] There are four lines of further advance open to an invader who has captured Almeida. The first, a march on Oporto via Pinhel and Lamego, may be mentioned only to be dismissed from consideration. It is of no use to an army which aims at Lisbon, and proposes to conquer Portugal by a blow at its heart. Masséna, whose directions were to drive the British into the sea in the shortest and most effective fashion, could not have contemplated such a secondary object as the capture of Oporto for a moment. There remain three other roads to be investigated.