Serjeanty in the Kingdom of Valyria is a form of fealty. Specifically it is classed not as homage, but as bondage, which is the fealty that coloni undertake. Serjeanty differs from other forms of subinfeudation, even for coloni, in that it involves constant military service without requiring a levy. The colonus swearing his fealty to a lord in this way has pledged to become a sergeant. Becoming a sergeant involves training, of course, and in terms of military rank, a new and unskilled colonus will begin at the rank of pedes before proceeding to miles and then, ultimately, serviens, which is Old Valyrian for sergeant.

One of the characteristics of serjeanty is that it does not involve the payment of rent as socage or burgage does, nor specifically the rendering of labor, as villeins and servants do. Sergeants swear to fight in the retinue of their liege lords, and that involves the donning of a uniform livery based on the lord’s coat of arms, as well as marching, muster, and castleguard. All of this is outlined in the vassal contract which exists between the sergeant and his lord as well as in the custumal which records it. Serjeanty also usually provides a place to live on the lord’s land, as in a barracks, or else within the lord’s hall or fortress.

Not all sergeants have necessarily taken a sworn oath of serjeanty. Because sergeant is not only a type of bondsmann, but also a military rank describing a quality of skill and equipment in a soldier, some freemenn serving in towns or mercenary companies are accounted as sergeants.