/u/Steelcan909 and /u/Bristoneman explain this blatant misinterpretation of Anglo-Saxon literature here.

Thanks to /u/BRISoneman for the summons. The question about whether the Anglo-Saxon giants were similar to those of Norse mythology is a generic yes, but the issue is extremely complex. Information about the early medieval traditions is scarce and scattered, making it difficult to be certain what people believed.

There is also the problem that written records may not accurately document the folk traditions of the time. In addition, we must keep in mind that folklore is fluid, so even an accurate description of tradition might not apply to the next generation or the next valley over.

That said, we can extrapolate a great deal from limited primary documentation from the early medieval period, particularly when we consider later folk traditions and how they seem to coincide with earlier mentions of traditions and legends associated with Northern European giants. Elisabeth Hartmann (1912-2005) published her impressive dissertation, Die Trollvorstellungen in den Sagen und Märchen der Skandinavischen Völker – The Troll Beliefs in the Legends and Folktales of the Scandinavian Folk, in 1936. In this, she included a chapter discussing the overlap of troll and giant traditions, doing some comparative analysis across the North Sea when it came to folklore about giants.

As correctly pointed out in this thread, giants were famous for large features in the landscape, and this motif is shared throughout the region. Importantly, people did not tell stories about seeing giants because people concluded that giants existed long ago, but either died out or only continued to live in distant places. This core, shared folk tradition allowed for “migratory legends” to spread throughout the region, being adapted to local situations and local geological features or enormous antiquities.

Here is an excerpt from my modest little publication, an attempt to “translate” my dear Hartmann’s work, both into English and into the twenty-first century (she assisted with this project before her passing):

People believed giants existed based on the existence of something unusual in their immediate environment. A famous example of this is preserved in the name of Northern Ireland’s “Giant’s Causeway.” Here, people regarded a peculiar rock formation as the ancient work of a large supernatural being. Later residents near England’s Devil’s Dyke in Cambridgeshire saw the long prehistoric earthwork as superhuman, crediting it to Satan. Though the devil is not a giant, his English dyke represents the same process of attributing a remarkable thing to a supernatural being’s effort long ago.

People looked at distinctive, unusual features in the world and arrived at extraordinary explanations for their origin. They believed a real, strange thing proved the existence of the supernatural being. After applying this backward form of logical deduction, cultures generally clothed the supernatural actor in more or less human form. Because people imagined the creatures walked the earth in the immediate past, these beings were distinct from gods or vague spirits, who existed in the present but could not be seen. Popular belief held that etiological beings like giants were real entities of substance that had, at one time, interacted with people. Descriptions of gods mingling with people also existed, but these usually belonged in a fantastic past, not in recent history.

So, what can we deduce given limited medieval documentation and widespread documentation from more recent folk traditions, gathered by folklorists? What seems to be occurring here is that there was a widespread folk tradition about giants throughout Northern Europe. These tended to be similar and were indeed sufficiently alike to allow legends to diffuse throughout the region, being adapted to local circumstances.

Were these giants (regardless of the century to be considered) identical on either side of the North Sea – either in the early medieval period or in the nineteenth century - for example? The answer is yes and no, and this is where it becomes complex. Again, folklore is fluid, so variation is an intrinsic characteristic of this aspect of culture.

Projecting into a past that we can only glimpse occasionally through the haze, it is likely that the respective giants on either side of the North Sea were similar enough that people recognized a similar motif when their cultures interacted. It is equally likely that people would have been struck by differences in traditions, perhaps concluding that the “other group” got “it” wrong, or perhaps concluding that the giants “over there” were simply a little different. It is very difficult to say how they would have viewed oner another’s folklore.

All that can be said with certainty is that while there seems to have been a similar shared tradition dating back centuries, variation necessarily ruled the day.

In Old English, giants are Enta, not Jotnar, but like the giants of Norse mythology, are thought to have been considered master builders.

I looked at the poem The Ruin and its giant-related imagery in this post, and Cohen (1993)'s assertion about the role of the giants as a cultural reference point in Early English poetry.