During the " Ancien Régime" each resumption of hostilities leads to creation or increase in strength of the light troops,which, although a very bad reputation are nevertheless essential for the armies of this period. Often associated with hussars or dragoons in their actions, light troops have a significant part in the development of the campaigns. They are responsible for the recognition of fords, defiles or bridges..., for the protection of the convoys, the contributions levy, they hold the advanced posts, reconnoitre enemy positions and movements. By their mobility and the speed of their actions they create a surrounding of insecurity around the enemy. They also participate in all the great battles but are more effective in skirmishes, in the lightning attacks, by surprise in difficult land unfavourable for the deployment of the regular troops.       The light troops as hussars are made up primarily with foreign mercenaries or deserters whith bad discipline, then the royal will to get better order by regulating their organization and entrusting their command to experienced officers, but by these reforms they often lost a part of their efficiency. The armies of the belligerents (Prussia, Austria, Hanover...) have all light troops or irregular forces but Frederic II is also in this field an innovator by systematic enlistment of all deserters and prisoners of war; thus each one of his victories is marked by creation of irregular forces, as after the invasion of Saxony in 1756, after the battles of Prague, Rossbach, Leuthen, Breslau.... and even a Russian irregular force after the campaign of Poméranie.       The poor reputation for reason of lack discipline of the light troops is unfortunately fully justified as wrotte Prunelle de Roison cornet in Royal dragoons, which regiment is sent in High-Frise to reduce the inhabitants of this area which refuse to pay the contributions and fight; he describes the Chasseurs de Fischer in a letter to his brother: " they are gallows birds made "of sacks and cords" (made for sackcs and cords of gallows) who make great carnage among the inhabitants ". This lack of discipline was not specific to french light troops it posed also problems for other armies as the exactions and the fire of the Dresden suburbs in 1759 by the Prussian irregular Freikorp of Meyer reported in the Gazette of Holland of this year.         All these " petites guerres " are dangerous and bloodies, so belonging to light troops ensure an higher pay than that of the regular troops. Pay paid by the King, added with the spoils taken on the inhabitant in enemy or allied territories or obtaining royal graces. In return they cant' have access to the royal hospitals.       At the begenning of the Seven Years War, at the end of 1756 , French has approximately 5.000 men enlisted in light troops, this number doubled in 1759 to reach nearly 12.000 men before the end of the hostilities. They will be brought back to 6 legions in 1763.       The organization of each corps was very variable, given to the appreciation of the colonel, generally including foot soldiers and riders. The ordinance of November 22, 1759 tries to unify the organization of the light troops, so the volunteers of Flandres, Hainaut, Dauphiné, Austrasie and Clermont Prince theoretically take the same organization of, 948 men dispatched into 17 companies with:       - a statff with 1 colonel, 1 lieutenant-colonel, 1 major, 2 aide-major, 1 chaplain and 1 surgeon.       -1 company of 3 officers and 60 grenadiers.             The grenadiers company: 1 captain, 2 lieutenants, 2 sergeants, 1 quartermaster, 4 corporals, 4 lance corporals, 1 drummer and 48 grenadiers.       -8 companies of 3 officers and 71 fusiliers.             Each company of fusiliers: 1 captain, 2 lieutenants, 3 sergeants, 1 quartermaster, 6 corporals, 6 lance corporals, 1 drummer and 54 fusiliers.       -8 companies of 4 officers and 40 dragoons.             Each company of dragoons: 1 captain, 1 lieutenant, 1 cornette, 1 maréchal-des-logis (sergeant), 1 quartermaster, 2 brigadiers, 1 drummer and 36 dragoons. This 18th century see the takeover by the King on the different army corps by suppression of the privileges and progressive buyback of all the military offices. The light troops were the last corps where the autonomy of organization, administration and clothing was left to their colonel. The ordinances of 1759, 1762 and finally that of 1776 will sound the death knell of the last regiments which the princes could raise to their name and their colors.