Scott ordered an attack on the convent. In addition to the stone walls of the convent, the defenses included a series of incomplete trenches the Mexicans had begun digging prior to the attack. Some elements of the Tlapa and Lagos Battalions arrived as reinforcements. Three cannon were placed on the right; two in the center; and the remaining two on the left. "Independencia" was assigned to defend the upper walls, the right flank leading to the bridge, the unfortified south and north sides, and two adobe huts further forward on the battlefield. The "Bravos" and the "San Patricios" were stationed on the left, behind barricades. In support along the Rio Churubusco was the Pérez Brigade: 2,500 men (11th Line, 1st, 3d & 4th Light Infantry Regiments).