As is the norm when discussing the history of Anglo-Saxon England, what we see in terms of military exploits is nothing as we would see it today. The idea of professional soldiers did not exist (though, the Normans would make strides toward forming such units); warriors were, presumably, skilled hunters and generally males within a certain age group. Tribal conflicts were communal affairs and usually revolved around hunting spaces or, in the case of developing social hierarchies, loyalty to specific kings and lords. Conflict around a national identity, obviously, was a thing still far in the future (it would not be until after the conclusion of the Hundred Years War that anything like a national identity would emerge), as was, for the most part, cultural conflict; indeed, it seems that the furthest conflict came in the cultural realm was when it involved the clash between paganism and Christianity as expressed through the friction between competing rulers.
For much of the seventh century, it was Northumbrian expansionism which dominated the period. Though eventually defeated by upstart leaders from the Southern Kingdoms (Mercia, which would eventually come to dominate England in later centuries), the intermittent warfare would become a symptom of the kings who would vie for control of specific stretches of land. Since many tribes’ nobility rested on a military aristocracy, a class of warriors which directly served their king, this focus on lordly dispute, is unsurprising.
Though Mercian supremacy in the south would last for a long while, eventually, around the 9th century, a dramatic reversal would occur which would put the Merican kingdom on the downfall; this was the period of House Wessex, but it was also the period of the Norman (re: ‘Viking’ invasion). England, with its relative wealth and fertile fields ripe for settling, appealed to the Viking warlords; so, hostility soon erupted between the peoples as Norman invaders came first in raiding parties and later as full-scale armies.
What many people tend to overlook about eh Norman invasion is that the conflict in the 860s is, in fact, the first Viking invasion. There was to be another secondary Viking invasion during the next century which would finally place Norman rulers in control of England. Though Alfred the Great would make peace with the Norman interlopers, thus giving him precious time to raise a formal army, and something closer to a professional fighting force, antics which would enable English cultural life to continue unabated, his successors proved to be only marginally as proactive as Alfred; eventually, due to a combination of several factors, the House of Wessex would shatter and the Norman takeover legitimated practically as the rightful heir to the throne.
And so is the military history of Anglo-Saxon England. All though very short, I wanted to give a brief overview of the basics of Anglo-Saxon bloodshedding. At a later date, I will publish a more protracted investigation on military actions and general history. Until that date, hold tight.