Great question! My answer is going to be intended for your question regarding the Anglo-Saxons; however, I’m going to take a slightly more abstract and historiographical approach to try and illustrate an important issue in asking such questions regarding identities, ethnography, culture, and so forth in the medieval period. This question has quite a lot of current historiographical relevance as significant controversy has erupted within the International Society for Anglo-Saxonists in 2019 concerning whether the society’s name was appropriate considering the appropriation of such medieval terms have been appropriated by various groups purporting racist and nationalist ideologies. For the purpose of this answer, I will make use of the term Anglo-Saxon, but I will attempt to explain it within the context of the potential issues of using any broad ethnographic term. Especially in the coming years, it is going to be essential for those in the field of medieval studies to ensure that the academically sound scholarship concerning such terminology reaches the public, instead of abandoning it in the face of malicious appropriation. If I’ve made any errors or if my answer is a bit jumbled/not making sense, do forgive me; I will be more than happy to correct or clarify anything – it can be a very confusing topic to discuss but it is definitely rewarding!

It’s important not to be dogmatic in approaching the question of identities in the medieval period. Many modern reconstructed maps in textbooks of the medieval period are just that – reconstructions based on (hopefully) the evidence, both material and textual, and everything between. A famous cartographical statement in map-territory relations (A map being an abstract representation of a territory, which is the subject in reality) is “the map is not the territory” – in other words, a map cannot claim to represent a reality unless the map was the same size and occupied the same space as its subject. It could be argued to some extent the map is the territory in the sense that it can tell you a lot about how those who made the map viewed the world and its inhabitants, with the map itself being a very real product of a contemporary world view.

You may be able to observe an “Ireland” in the middle ages with people speaking a roughly similar language and quite possibly exuding a vague sense of a common realm, but Ireland was divided into many Kingdoms at this time. It is quite the same case with regard to the “Vikings” – they may have come from the same or relatively nearby lands, and spoken a fairly homogenous language, but Norway too was fractured into many kingdoms. This is not to say that this extreme volume of political entities creates equally disparate cultures, but it is just a reminder to exercise caution that identity in the medieval period is going to be difficult establish consistent and meaningful categories – it will reward us better to study different regions and their cultures to paint an image of commonalities, differences, and exchanges of culture and make connections rather than to rely on potentially misleading or oversimplified categories of peoples and nations - many of which were constructed during the period of romantic nationalism in the 19th century (especially in the case of the Vikings); it is very important to challenge these assumptions.

The term “Anglo-Saxon” is used in the most up-to-date sound scholarship; however, it is certainly debatable that it does hide the true extent of the nature of the identities of those who lived in pre-Norman England. The term originates from a combination of what the Venerable Bede (7-8th c. Anglo-Saxon scholar) called Angli and Gildas (6th c. Roman scholar) Saxones, but many other distinct groups from the North Sea coast would have also taken part in the migration which the term does not illustrate, including the Jutes and a multitude of tribes from the present-day low countries. The reality being, a series of created identities (by the primary sources, and later scholarship) as being nodal points between an infinite spectra of interconnected identities – if scholarship is to use such a term, it ought to have the responsibility of discerning that reality – that it is a compromise, and not an attempt to establish a uniform identity that does not truly exist (if you are interested, Benedict Andersson’s Imagined Communities is a highly recommended book on this topic in a modern context).