   man-at-arms was a term used from the high medieval to renaissance periods to describe a soldier, almost always a professional warrior in the sense of being well-trained in the use of arms, who served as a fully armoured heavy cavalryman. it could refer to knights or noblemen, and to members of their retinues or to mercenaries in companies under captains. such men could serve for pay or through a feudal obligation. the terms knight and man-at-arms are often used interchangeably, but while all knights equipped for war certainly were men-at-arms, not all men-at-arms were knights. == evolution of the man-at-arms == in the early medieval period, any well-equipped horseman could be described as a "knight", or miles in latin.church and harvey (1994), p. 51. in the course of the 12th century knighthood became a social rank with a distinction being made between milites gregarii (non-noble cavalrymen) and milites nobiles (true knights).church and harvey (1994), pp. 48-49. as a fully armoured cavalryman could be of a lesser social status than a knight, an alternative term describing this type of soldier came into use which was, in french, homme d'armes or gent d'armes, and in english man-at-arms. the term man-at-arms thus primarily denoted a military function, rather than a social rank. this evolution differed in detail and timeline across europe but by 1300, there was a clear distinction between the military function of the man-at-arms and the social rank of knighthood.nicholson (2004), p. 55. == terminology == though in english the term man-at-arms is a fairly straightforward rendering of the french homme d'armes, in the middle ages, there were numerous terms for this type of soldier. in france, he might be known as a lance or glaive, while in germany a spiess, helm or gleve and in various places a bacinet. in italy, the term barbuta was usedmallett (1974), pp. 31-2. and in england from the late 14th century, men-at-arms were known as lances or its english equivalent, spears. == military function == the military function that a man-at-arms performed was serving as a fully armoured heavy cavalryman; though he could, and in the 14th and 15th centuries often did, also fight on foot. in the course of the 16th century, men-at-arms increasingly serve as other cavalry types, the demi-lancer and the cuirassier. === arms and armour === throughout the medieval period and into the renaissance the armour of the man-at-arms became progressively more effective and expensive. 
16th-_and_17th-century_warrior_types Cavalry Combat_occupations Military_units_and_formations_of_the_Early_Modern_era Military_units_and_formations_of_the_Hundred_Years\'_War Obsolete_occupations