I'm studying the customs of medieval Europe to gather information for a novel I'm writing and a question has arisen about how the nobles, especially the royal family, identified themselves. Did they use their surname/family name or did they use the country/kingdom to which they belonged? For example, if we were in the Middle Ages, Anne (the daughter of Queen Elisabeth II) would be Anne of the United Kingdom or Anne Windsor/ of the House of Windsor. And if both are correct, which would be the most common? My doubt arises because for example Queen Elisabeth (wife of Edward IV) was called Elisabeth of York (York was the royal house to which she belonged), while Queen Catherine (first wife of Henry VIII) was called Catherine of Aragon (Aragon was the country to which she belonged). It may also be that this is due to the names that historians have subsequently chosen. If this is the case I ask again how they were usually called in their time. As I understand it, the nobles, who did not belong to the royal family, did use the family surnames. All this has come up to me because I am a big fan of Game of Thrones, which is also slightly based on the Middle Ages, and there all the characters (or almost all of them) are identified with their first name + their family surname; and I wondered if in medieval Europe this also happened. I don't want my novel to be a copy of Game of Thrones and that's why I prefer to base it on what really happened in the Middle Ages.
If you could inform me about Spain and England in the years 1400-1500. And if it could be that they were not examples but the common way in which nobles and members of the royal family were identified in their time.