No hammer has ever been found in a context suggesting it’d be used as a weapon. The largest find of Viking Age hammers by far was in the the Mästermyr toolchest, which is obviously a tool-related context. There have also been finds of a few small bone/horn hammers, (mainly in ‘svarta jorden’ in Birka) but those are of unclear function, perhaps ceremonial akin to Sami magic-drum hammers.
It’s far from obvious what benefit in combat these ordinary hammers could possibly have over the most common Viking Age weapon we know, namely axes. Axes had other uses as well, which is why they were common, and why swords are associated with the elite; it’s an expensive single-use-item, used almost exclusively for combat (and somewhere in-between you have spears).
As for Thor’s hammer (‘Mealer’) was it really the ‘principal symbol of their faith’? The oldest ritual use of (possible) hammers is on amulet rings, which are rings that seem to have been put on posts at a vi (outdoor cult site), which had little pendants on them. Some had rings on the ring, others a hammer-like ornament, still others a more l-shaped thing (possible scythe) others axe-head like and some a flat washer-like thing. On the assumption that the T-shaped ones are hammers it’s been though those might be Thor symbols, but it’s also been argued that as T or “tau-cross”-like objects they’re fairly generic and could mean lots of things. None of the others have any specific interpretations. But in any case these were old, ritual objects that go back centuries before the Viking Age.
Another, possibly analogous thing, are miniatures that have been found in grave goods. These mainly precede the Viking Age (mainly 6th to 8th centuries) It’s unclear if they had ritual purpose, were amulets or simply jewelry or all the above but it’s notable that the miniatures tend to be everyday objects and – with the possible exception of the hammer – not ones so specific as to be associated with a particular god. (To quote Fuglesang: “Another peculiarity of the Viking amulets is the absence of close connections with pagan gods; apart from the Thor’s hammer, there is no verifiable instance of divine attributes used as amulets”). Miniatures also occur on the continent prior to being found Scandinavia; it may have been a foreign influence.
The Thor’s hammer pendant on the other hand, is as far as anyone knows, a distinct tradition, at least from the amulet rings but not necessarily the miniatures. It does not predate the Viking Age but appears first in the 9th century; i.e. post-Christian contact. Therefore it’s usually assumed to have been a reaction to the Christian crucifix.
What sort of reaction is another matter. It could naturally be a counter-reaction where it was created as a new symbol of the ‘old ways’ in the meeting between the religions. Or just simple imitation. Another possibility is syncretism; a mixing of Christianity and Norse beliefs. The motif of Thor’s Fishing, with Thor brandishing his hammer, occurs in several Christian contexts (the Gosforth Cross and Altuna Runestone). On some occasions both crucifix and hammer amulets have been found in the same graves, and a mold found in Denmark is a double that allows for casting both items.
However the tool and weapon miniatures have so far been found exclusively in female graves. But not the hammer, (although mostly so quite overwhelmingly). The possible special purpose to women has suggested to be a fertility symbol and Thor perhaps playing a role as fertility god.
Yes, “fertility god”, not the “fiercest war Deity’. The mythological stories of the Eddas are a distinct thing from, and poor guide to, the actual practical cult. Adam of Bremen for instance, who unlike the recorded skaldic poetry was describing the cult, (even if it’s a second- or third-hand account), portrays Thor instead as a god of weather and good harvests and a fertility god in the crop sense (albeit not for humans, which is attributed to ‘Fricco’ instead).
There are many place names for Thor (although complicated by the fact that his name is also the word ‘thunder’) but it’s rather striking that there’s only a single place name in Sweden that means “Thor’s vi ” (out of 57 Thor-related medieval place names), as opposed to 6 “Odensvi”, about 7 “Frövi” and over 20 “Ullevi”. In other words, as far as place-names are an indication, Ullr, a god barely mentioned in the Eddas, may have had the most widespread veneration by quite a bit. We won’t get deep into the possible explanations for this (e.g. certain gods being more associated specifically with worship at vi-sites) but the bottom line is that the Eddas are a poor guide to the how and why these gods were worshiped.
When it comes to vi sites and other empirical evidence, it doesn’t show any particular significance to the Æsir-Vanir distinction either. Some have even questioned whether there ever was one in the first place or ‘vanir’ was just a less common term that Snorri just interpreted as a specific group.
Anyway, even by the Eddic accounts, Thor’s hammer functions as much more than a weapon. The fact that it is used to bless a marriage in Þrymskviða (Poetic Edda) On the other hand, Adam claims it’s Fricco that sacrifices are made to if marriages are consecrated. (“si nuptiae celebrandae sunt“). The image of the actual cult is fragmentary and contradictory, as opposed to the relatively-speaking cohesive narratives of the Eddas. So we know a lot about the stories in the Eddas, but not so much about the practical religion. Including what the Thor’s hammer amulets signified, and indeed, in many cases we can’t be 100% sure whether the ‘hammers’ really were intended as symbols of Thor.
In summary though: Hammers were not used as weapons. Thor’s own hammer in the Eddas was not used exclusively as a weapon. Thor’s hammer amulets (if they do represent “Mealer”) do not seem to have been perceived as a weapon since they were not used in the same way as the small swords, lances and other miniatures/amulets in grave goods.
2. M. Koktvedgaard Zeiten, Amulet and Amulet use in Iron Age Denmark. Acta Archaeologica, v68. 1–74. (1997).
3. Erika Rosengren – Miniatyren – ingen småsak. En presentation av en alternativ tolkning till vapen- och redskapsminiatyrer i Uppåkra in Från romartida skalpeller till senvikingatida urnesspännen Nya materialstudier från Uppåkra, Acta Archaeologica Lundensia, No 61 (2010).
4. Stefan Brink – How Uniform Was Old Norse Religion? in Learning and Understanding in the Old Norse World: Essays in Honour of Margaret Clunies Ross (2007).
5. Rudolf Simek The Vanir: An Obituary, RMN Newsletter No 1, (2010).
6. Written by u/Platypuskeeper.