Is there anywhere where I could look up how much land a noble landholder held? In books you often find descriptions like "Warwick held several manors and increased his land through adding the Beaumont-estates" but I would like to know what exactly that means.
Thanks in advance for anwers!
It depended on how many lordships/dukedoms/earldoms that lord had.
I can give you some references about some Castilian nobles from the Late Middle Ages.
Don Juan Manuel, prince of Villena, duke of Peñafiel, etc held a substantial amount of land: more or less the current province of Albacete was his, and that even protruded a bit getting as well Villena (province of Alicante) and to the Northwest the limit of his fiefdom was Belmonte (province of Cuenca). He also held Peñafiel (province of Valladolid), but that was another fiefdom.
Don Íñigo López de Mendoza, marquess of Santillana, held enough fiefdoms that all his sons got some ludicrously large land holdings: Guadalajara, Hita, Buitrago de Lozoya, Fresno de Torote, Monedero, Uceda, Manzanares el Real, Santillana del Mar, the lordship of La Vega, about half of present day Cantabria, Pastrana, Tendilla, Coruña del Conde, Saldaña, Carrión, Mendoza, and a surprisingly long et caetera.
Sources: Fernández de Oviedo, Gonzalo, Batallas y Quinquagenas, vol. 1, Madrid: RAH, 1983.
Don Juan Manuel, El conde Lucanor.