However that may be, the programme was at once stultified by the unexpected speed and force of the German approach. The bombardment of the nine forts of Namur had begun on August 20. Bülow’s Army reached the Sambre on the following day, and held the passages at night. Lanrezac’s orders had become plainly impossible, and he did not attempt to fulfil them. Early on the afternoon of the 21st, while Kluck approached on one hand and Hausen on the other, Bülow’s X Corps and Guard Corps attacked the 3rd and 10th Corps forming the apex of the French triangle. These, not having entrenched themselves, and having, against Lanrezac’s express orders, advanced to the crossings between Charleroi and Namur, there fell upon strong defences flanked by machine-guns, and were driven back and separated. Despite repeated counter-attacks, the town of Chatelet was lost. On the 22nd, these two French corps, with a little help from the 18th, had again to bear the full weight of the enemy. Their artillery preparation was inadequate, and charges of a reckless bravery did not improve their situation.[24] Most desperate fighting took place in and around Charleroi. The town was repeatedly lost and won back by the French during the day and the following morning; in course of these assaults, the Turcos inflicted heavy losses on the Prussian Guard. While the 10th Corps, cruelly punished at Tamines and Arsimont, fell back on Mettet, the 3rd found itself threatened with envelopment on the west by Bülow’s X Reserve and VII Corps, debouching from Chatelet and Charleroi.