In October 1916 a training centre for personnel was established at Champlieu, on the southern edge of the Forest of Compiègne, and here in December the first lot of sixteen Schneider Tanks were delivered, other batches both of Schneiders and St. Chamonds following them during the succeeding months, until, in April 1917, nine Schneider Companies and one St. Chamond Company and their crews were ready for action. On April 16, 1917, French Tanks took part in their first battle, fighting with the 5th French Army in the attempted penetration of the Chemin des Dames. Of the eight Schneider Companies employed, five succeeded in reaching their third and final objectives, but owing to lack of previous training with the infantry, the attack as a whole was not very successful, and the Tanks, though they played an exceedingly gallant part, suffered severely. A week or two later, one St. Chamond and two Schneider Companies took part in a hurriedly prepared operation with the 6th Army. The Schneiders did extremely well, but of sixteen St. Chamond machines, only one managed to cross the German trenches. All through the summer months, the 6th French Army was preparing another attack on the west of the Chemin des Dames, and for this battle, warned by their previous experiences, infantry and Tanks trained diligently together, special detachments known as _troupes d’accompagnement_ being taught how to help the Tanks over trenches. But the agile mind of Colonel Estienne was not content. He had had another idea. This time his mind had worked at the idea of the armoured attacking force from a slightly different standpoint. He envisaged waves of armoured skirmishers attacking in open order, each man possessing besides his armour a quick-firing weapon with which he could shoot as he advanced. Now, armour which will protect from machine-gun and rifle fire is too heavy for human legs. The armour must be independently propelled. More, if its occupant is to fire as he advances, it must carry him as well as itself. This postulates an engine, and if there is an engine, there must be a second man to look after it. This set of propositions he laid before the Rénault firm in July 1916, and the design of the famous Rénault Tank was evolved. But the Ministry would have none of it. However, the designs were worked out in greater detail, and at the end of November 1916 Colonel Estienne proposed to the Commander-in-Chief that a number of such machines should be constructed. A few, he explained, had already been ordered to act as “Command” Tanks for the heavy Battalions. The Commander-in-Chief consented to a trial. This, however, was not held until March 1917, and when it had been held, the Ministry were still not convinced. Therefore, still further demonstrations were arranged in May, when at last they ceased to doubt, and finally, in June 1917, ordered 3500 of the new machines.