Ægishjálmur
An eight-armed Icelandic stave of protection and terror. The word is Old Norse; the design that people tattoo is early modern.
The drawing above shows one form of the symbol. Historical examples vary (sometimes considerably), and no single version should be treated as canonical.
Earliest attestation: Word 13th century; the drawn stave 17th century
The oldest surviving appearance we can actually point to.
The word ægishjálmr occurs in medieval Old Norse literature: Fáfnismál and Vǫlsunga saga describe the dragon Fáfnir wearing one to terrify all who approached. The drawn stave belongs to the Icelandic grimoire tradition instead, and the familiar eight-armed form is best attested from the 17th century onwards, in manuscripts such as Galdrakver (Lbs 143 8vo, 1670) and later in the Huld Manuscript.
Historical use
The distinction matters: the medieval texts describe a helm or a power, never a diagram. The visual design belongs to the same post-medieval Icelandic stave tradition as the vegvísir, in which staves were drawn on lead, wood or skin and used for specific practical purposes.
Modern use
Used today as a protection symbol in heathen practice and very widely in tattoo work, usually presented as Viking-Age. Some far-right groups have also adopted it.
Common misconceptions
Claims about this symbol that circulate widely and do not hold up.
The name is old and the picture is not. Sources that show the eight-armed stave and cite Fáfnismál are combining a 13th-century text with a drawing several centuries younger. Exactly which grimoire the eight-armed form first appears in is itself disputed, which is a fair measure of how thin the evidence is.
The arms of the ægishjálmur are not algiz runes repeated eight times. That reading is a modern rationalisation.
Sources
Full references on the sources page.