Runic Inscriptions
Another source of information about Germanic culture is runic inscriptions.
The first example, on the Etruscan Negau helmet, variously dated as approx. either 300 or 400 BCE, is actually not in runes but in a North Italic alphabet.
It reads "HARIGASTI TEIWAI," which may be interpreted either as "to the god Harigast (i.e. Óðinn/Wóden/Wodan)" or "Óðinn and Týr!" (Thorsson 8)
The earliest known example of actual runes, in the Elder Fuþark, is the Meldorf brooch from the west coast of Jutland, approx. 50 CE (Thorsson 9, 11). Until
it was discovered, the earliest runic inscriptions were thought to be other pieces of jewelry and weapons of the 3rd century CE (and some argue that the
Meldorf inscription is in fact still North Italic). Most of the early runic inscriptions are brief and hard to interpret. Many involve repeated rune staves
(letters) or the entire fuþark, indicating magical intent.
From approx. 800 CE, Scandinavian inscriptions are instead in the Younger Fuþark, which reduces the number of staves from 24 to 16. Although the intended
sound is sometimes indicated by adding a dot, it is hard to avoid concluding that the intent was to make it harder to read the inscriptions, particularly since
Old Norse had been adding sounds rather than losing them. The vast majority of runestones are in this fuþark. Some require even more decoding, indicating the
ætt (group) within which the intended stave is to be found and its number within it rather than actually using the rune stave.
The Anglo-Frisian Fuþorc, in contrast, expanded the 24 staves to 26 (33 in Northumbria). It was used for inscriptions in Anglo-Saxon and Frisian, hence the
name, and because of sound changes, assigns different values to several staves. It was used for Xian inscriptions and more freely than the Scandinavian
Fuþarks, with no evidence of concealment of meaning.
Even with the broader use of the Anglo-Frisian runes, the runic corpus gives a strong impression that runes were used for special purposes - in Scandinavia,
overwhelmingly to mark personal possessions (especially weapons), for dedications to gods and magic, and in later centuries on memorial stones. This is in
contrast to the use of the Latin alphabet from the earliest times for recording literary works, for bawdy graffiti, and for mundane lists and accounts; after
the introduction of Xianity the two scripts coexisted for centuries, but were used for different purposes. A large number of runic inscriptions have
undoubtedly been lost, particularly since the script was originally intended for etching into wood. The exception that proves both rules is a large trove of
runic inscriptions on bone and wood - including slips of wood that must have been used as markers or labels, as well as wooden objects - from Bryggen, the
ancient Hanseatic wharf in Bergen, Norway. Several of these are mundane: OST MIN KIS MIK ("My darling, kiss me") on a stick, business letters and orders. But
the largest number are name markers, many (including the love-stick) have the fuþork written out in whole or in part in the old magical way, and some are Xian
charms. And they are very late and fully Xian in date: from the 14th century CE. So they do nothing to change the impression that writing was thought of
differently in the Germanic sphere than in the Hebrew and Greco-Latin sphere that gave rise to the ideas about and uses of literacy after the conversion. They
demonstrate what the transition looked like - and the fact that runes were usually cut in more ephemeral materials than stone.
Another valuable runic inscription that should be mentioned is on the back of the Nordendorf fibula, an early seventh century Alemannic brooch. Two words
are interpreted as a dedication: AWA LEUBWINIE, ("from Ava to Leubwini"?) Upside down in relation to that are three lines of runes that seem to name gods:
LOGAÞORE WODAN WIGIÞONAR (de Vries 1 310-11). The last of these may be equivalent to ÞUR UIKI in tenth-century Danish inscriptions, so it would mean "Thor
hallow" (Turville-Petre 101). The middle one is Óðin's name in Old High German. The first could be the only attested occurrence of Loki's name outside
Scandinavia; or it could be a blessing; or Klaus Düwel has recently suggested it means "deceiver" (there is an Anglo-Saxon word logðor or logeðer meaning
"maleficent, crafty"), in which case it would mean "Odin and Thor are sorcerors." Either way it is among the very few pieces of evidence of continental
heathenry.
Map of where Elder Fuþark inscriptions have been found:

Map created by Berig, Wikimedia Commons
Negau helmet inscription:

Image by Dbachmann on en.wikipedia ([1]) [Public domain], via
Wikimedia Commons
For more information on the Negau helmet see Wikipedia.