Wiktionary
n. (context historical English) a nobleman who fought alongside his monarch in battles and who held tenants directly from the crown
Wikipedia
__NOTOC__ In medieval and early modern Europe the term tenant-in-chief (or vassal-in-chief), denoted a person who held his lands under various forms of feudal land tenure directly from the king or territorial prince to whom he did homage, as opposed to holding them from another nobleman or senior member of the clergy. The tenure was one which denoted great honour, but also carried heavy responsibilities as the tenants-in-chief were originally responsible for providing knights and soldiers for the king's feudal army. Other names for tenant-in-chief were captal or baron, although the latter term came to mean specifically one who held in-chief by the tenure per baroniam, the feudal baron. The Latin term was tenens in capite; In most countries allodial property could be held by laypeople or the church; however in England after the Norman Conquest, the king became in law the only holder of land by allodial title; thus all the lands in England became the property of the Crown. A tenure by frankalmoin, which in other countries was regarded as a form of privileged allodial holding, was in England regarded as a feudal tenement. Every land-holding was deemed by feudal custom to be no more than an estate in land whether directly or indirectly held of the king; absolute title in land could only be held by the king himself, the most anyone else could hold was a right over land, not a title in land per se. In England, a tenant-in-chief could enfief, or grant fiefs carved out of his own holding, to his own followers. The creation of subfiefs under a tenant-in-chief or other fief-holder was known as subinfeudation. The Norman kings, however, eventually imposed on all free men (i.e. those whose tenures were "freehold", that is to say for life or heritable by their heirs) who occupied a tenement a duty of fealty to the crown rather than to their immediate lord who had enfeoffed them. This was to diminish the possibility of sub-vassals being employed by tenants-in-chief against the crown.
The lands held by a tenant-in-chief in England, if comprising a large feudal barony, were called an honour. As feudal lord, the king had the right to collect scutage from the barons who held these honours. Scutage was a tax collected from vassals in lieu of military service. The payment of scutage rendered the crown more independent of the feudal levy and enabled it to pay for troops on its own. Once a tenant-in-chief received a demand for scutage, the cost was passed on to the sub-tenants and thus came to be regarded as a universal land tax. This tax was a development from the taxation system created under the Anglo-Saxon kings to raise money to pay off the invading Danes, the so-called Danegeld.
In the great feudal survey Domesday Book (1087), tenants-in-chief were listed first in each county's entry. When an English tenant-in-chief died, an inquisition post mortem was held in each county in which he held land and his or her land temporarily escheated (i.e.reverted) to the demesne of the crown until the heir paid a sum of money (a relief), and was then able to take possession ( livery of seisin) of the lands. However, if the heir was underage (under 21 for a male heir, under 14 for an heiress) they would be subject to a feudal wardship where the custody of their lands and the right to arrange their marriage passed to the monarch, until they came of age. The wardship and marriage was not usually kept in Crown hands, but was sold, often simply to the highest bidder, unless outbid by the next of kin. When an heir came of age, he or she passed out of wardship but could not enter upon their inheritance until, like all heirs of full age on inheritance, they had sued out their livery. In either case, the process was complicated. Eventually a warrant was issued for the livery to pass under the Great Seal. From its inception in 1540, The Court of Wards and Liveries administered the funds received from the wardships, marriages and the granting of livery; both courts and practice were abolished in 1646 and the whole system of feudal tenure was abolished by the Tenures Abolition Act 1660.