Accordingly the Duke of Elchingen marched from the camp in front of Saragossa with the divisions of Marchand and Dessolles, and the cavalry brigades of Beaumont and Digeon. At Calatayud he came up with the force which had been dispatched in pursuit of Castaños,--Musnier’s division of the 3rd Corps, and that of the 6th Corps which Maurice Mathieu had taken over from Lagrange, who had been severely wounded at Tudela[104]. Leaving Musnier at Calatayud to protect his communications with Aragon, Ney picked up Maurice Mathieu, and passed the mountains into New Castile, where he fell into the Emperor’s sphere of operations. We have seen that he took a prominent part in the pursuit of Sir John Moore and the invasion of Galicia. [104] Few of the French historians mention these changes, but they are quite certain. On Nov. 23 ‘the division Maurice Mathieu’ means the 1st of the 3rd Corps; on Dec. 1, it means the 2nd of the 6th Corps. Moncey, meanwhile, was left in front of Saragossa with his 1st, 3rd, and 4th Divisions--the 2nd being still at Calatayud. This force consisted of no more than twenty-three battalions, about 15,000 men, and was far too weak to undertake the siege. The Marshal was informed that the whole corps of Mortier was to be sent to his aid, but it was still far away, and with very proper caution he resolved to draw back and wait for the arrival of the reinforcements. If the Spaniards got to know of his condition, they might sally out from Saragossa and attack him with more than 30,000 men. Moncey, therefore, drew back to Alagon, and there waited for the arrival of the Duke of Treviso and the 5th Corps. It was not till December 20 that he was able to present himself once more before the city.