The first tanks and units composed of them appeared in the French army during World War I as a remedy for the stalemate of the positional war on the Western front. Interestingly, however, unlike Great Britain, the initiative to build them came from French economic entities and defense companies rather than the French army. On the other hand, among the French officers, there were many supporters of introducing new weapons to the line, and Colonel Estienne deserves special emphasis. It is assumed that the first tanks of the French armed forces were the not very successful Schneider CA1 vehicles, and from April 1917, another heavy tank, the Saint-Chamond, was delivered to the units. In the same year, a truly revolutionary vehicle was introduced into service: the Renault FT-17 light tank, widely recognized as the most successful tank in its class in the Great War. This vehicle had a rotating turret with main armament, was much cheaper to produce than the Schneider CA1 or Saint-Chamond, and was better suited to combat in trench war realities. These tanks played a great role in the French and Allied offensives at the end of the First World War, contributing in no small way to the defeat of the German army.
At the time of the outbreak of World War I, the German army, like any other European army of that time, did not have any tanks. However, in the course of this conflict, Germany managed to overtake France, especially Great Britain, which had already, in 1916, introduced the first tanks on a large scale at the end of the Battle of the Somme. For the German army, the appearance of Mark IV tanks was quite a surprise, which became a catalyst for the development of their own armored forces. It also led to the design of the first German tank, the A7V, which had a crew of at least 18 people! The German army, however, still treated this type of weapon as of secondary importance and was aware that the economic opportunities of Germany did not allow for the production of tanks in large numbers. For this reason, it first used armored weapons on a larger scale only at the beginning of 1918, during the so-called Ludendorff offensives on the Western Front. It is worth adding that not only the native A7V was used in its course, but also many captured tanks, especially British ones.
The British Tank Corps was formed in 1916 as the Heavy Section Machine Gun Corps, a unit consisting of completely new combat vehicles, i.e., tanks. In July, it changed its name to the Armored Corps. The unit was used in combat for the first time on a larger scale during the fighting on the Somme on September 15, 1916. It was also the first large-scale combat use of the tank in military history. On a really massive scale, the British command used it Tank Corps during the Battle of Cambrai in 1917, when as many as 476 tanks entered the action! Also in August 1918, during the Battle of Amiens, armored forces were used on a large scale. It is worth adding that the Tank Corps served primarily on the Western Front of the Great War; only a few of the vehicles from this unit were transferred to the Middle East in early 1917 to fight against Ottoman Turkey. From November 1916 on, the basic organizational unit of the Corps was a tank battalion composed of three companies. One battalion served 32 officers and 374 non-commissioned officers and soldiers. At the end of World War I, as part of the Tank Corps, approximately 22,000 men.