Massena commenced his march into Portugal upon the 16th of September; his army advanced in three corps; the 8th corps under Junot, moved by Pinhel upon Trancoso, the 6th corps under Ney, upon Alverca; and the 2d corps, under Regnier, upon Guarda; the British cavalry retired to Celorico. The next day the two latter corps moved into Celorico; from which place they were observed to take the road to Fornos. As soon as Lord Wellington was persuaded that the enemy had made choice of that road, and that no part of their army was moving upon the road by the Tagus, he sent directions to Lieutenant General Hill to break up from Sarzedas, and to move by Pedragoa Grande, to the Puente de Marcella; he moved the corps of Major General Leith to the same place from Thomar, and he withdrew his own divisions with the view of collecting the whole army upon the Sierra of Busaco. Marshal Massena had commenced his operations with the hopes of turning the left of Lord Wellington, and of reaching Coimbra before the British army could be collected to oppose him; he had been induced to believe that Lord Wellington had prepared to meet him at the Puente de Marcella; but he hoped that by this movement on the right of the Mondego, he should turn that position, and find Lord Wellington unprepared to assemble in any other. He was miserably deceived; Lord Wellington was aware of the nature of the roads the enemy had fixed upon for his movements; he calculated the delays he would meet with, and arranged his plans accordingly. He directed a portion of the militia that was at Lamego under the orders of Colonel Trant to march upon Sardao; the rest was directed to move upon Trancoso and Celorico, upon the rear of the enemy, to intercept their communication with Almeida. Marshal Massena arrived at Viseu upon the 19th of September; his artillery had suffered so much from the badness of the roads that he was obliged to remain there for some days to repair it. General Junot joined him at this place from Trancoso, so that the whole French army was collected there. On the 23d the advanced patroles of the British and French armies met each other near St. Comba de Dao. The bridge over the Cris, by which the great road to Coimbra passes, was blown up; but the following day the French advanced guard passed that river, and the greatest part of the British retired to the heights of Busaco, where the whole army was collecting. On the 25th Marshal Massena joined his advanced guard, and on the 26th pushed forward to the foot of the position which was occupied by Lord Wellington.