On April 10, Suchet arrived at Monzon with a brigade of infantry, and the six companies of artillery and four of engineers which were destined for the siege of Lerida. On the thirteenth he was before the walls of the place on the west bank of the Segre, while on the next day Habert appeared on the other bank, driving before him Colonel Perena and his battalions. This second French column had passed the Segre at Balaguer, from which it had expelled the Spanish brigade. Perena, having the choice between returning into the mountains or strengthening the garrison of Lerida, had taken the latter alternative. On the same day Musnier came up from the South, and joined the army with the force that had started from Alcañiz and had crossed the Ebro at Flix. Suchet had now concentrated the whole of the 13,000 men[355] whom he destined for the siege. [355] For his strength at this moment, see the table which he gives in his _Mémoires_, vol. i, Appendix 4. His figures cannot always be trusted: for instance, purporting in this table to give his whole force, present at Lerida or detached in Aragon, he omits the six squadrons of gendarmerie which were guarding his rear [37 officers, 1,121 men] and the four battalions of _Chasseurs des Montagnes_, who were garrisoning Jaca, Venasque, &c. [about 2,000 men]. The town of Lerida, then containing some 18,000 inhabitants, lies in a vast treeless plain on the western bank of the broad and rapid Segre. Its topography is peculiar: out of the dead level of the plain rise two steep and isolated hills. One of these, about 800 yards long by 400 broad, and rising 150 feet above the surrounding flats, is crowned by the citadel of the town; the other, somewhat longer but rather narrower, is no other than the hill about which Caesar and Afranius contended in the old Civil Wars of Rome, when Lerida was still Ilerda. It lies about three-quarters of a mile from the first-named height. In 1810 its culminating summit was covered by a large work called Fort Garden, and its southern and lower end was protected by the two small redoubts called San Fernando and El Pilar. The town occupies the flat ground between the citadel-height and the river. It has no trans-pontine suburb, but only a strong _tête-du-pont_ on the other side of the Segre. The strength of the place lay in the fact that its whole eastern front was protected by the river, its whole western front by the high-lying citadel. The comparatively short southern front was under the guns of Fort Garden, which commanded all the ground over which an enemy could approach this side of the town. There only remained, unprotected by outer works, the northern front, and this was the point which a skilful enemy would select as his objective. Another fact which much favoured the defence was that the besieger was forced to make very long lines of investment, since he had to shut in not only the town, but the whole plateau on which lie Fort Garden and its dependent works.