Valknútr

The valknut (coined from Old Norse valr, "slain warriors" and knut, "knot") is a symbol consisting of three interlocked triangles. It appears on a variety of objects from the archaeological record of the ancient Germanic peoples. The compound noun valknut is from the modern era. The term used for the symbol during its historical employment is unknown.

Scholars have proposed a variety of explanations for the symbol, sometimes associating it with the god Óðinn, and it has been compared to the three-horned symbol found on the 9th-century Snoldelev Stone, with which it may be related. The valknut receives sporadic use in modern popular culture and is again associated with Germanic paganism by way of its modern day revival, Heathenry.

Archaeological record
The valknut appears on a wide variety of objects found in areas inhabited by the Germanic peoples. The symbol is prominently featured on the Nene River Ring, an Anglo-Saxon gold finger ring dated to around the 8th to 9th centuries. A wooden bed in the Viking Age Oseberg Ship buried near Tønsberg, Norway features a carving of the symbol on an ornately stylized bedpost and the Oseberg Tapestry, a partially preserved tapestry found within the ship burial, also features the symbol. Additionally, the valknut appears prominently on two picture stones from Gotland, Sweden: the Stora Hammars I stone and the Tängelgårda stone.

The historically attested instances of the symbol appear in two traditional, topologically distinct, forms. The symbol appears in unicursal form, topologically a trefoil knot also seen in the triquetra. This unicursal form is found, for example, on the Tängelgårda stone. The symbol also appears in tricursal form, consisting of three linked triangles, topologically equivalent to the Borromean rings. This tricursal form can be seen on one of the Stora Hammars stones, as well as upon the Nene River Ring, and on the Oseberg ship bed post. Although other forms are topologically possible, these are the only attested forms found so far.

In Norwegian Bokmål, the term valknute is used for a polygon with a loop on each of its corners. In the English language the looped four-cornered symbol is called Saint John's Arms.

Theories and interpretations
Several explanations for the symbol have been proposed:

Hrungnir's heart
Chapter 17 of the 13th century Prose Edda book Skáldskaparmál contains the following description of the heart of the Jǫtunn Hrungnir; "Hrungnir had a heart that was famous. It was made of hard stone with three sharp-pointed corners just like the carved symbol hrungnishjarta [Hrungnir's heart]." Comparisons have been made between this symbol description and the symbol known as the valknut.

Odin and mental binds
Hilda Ellis Davidson theorises a connection between the valknut, the god Óðinn and "mental binds":

For instance, beside the figure of Odin on his horse shown on several memorial stones there is a kind of knot depicted, called the valknut, related to the triskele. This is thought to symbolize the power of the god to bind and unbind, mentioned in the poems and elsewhere. Odin had the power to lay bonds upon the mind, so that men became helpless in battle, and he could also loosen the tensions of fear and strain by his gifts of battle-madness, intoxication, and inspiration.

Davidson says that similar symbols are found beside figures of wolves and ravens on "certain cremation urns" from Anglo-Saxon cemeteries in East Anglia.

Other
Due to the fact that the symbol appears on picture stones with Óðinn and on burial gifts in the Oseberg ship burial, Rudolf Simek says that the symbol may have been associated with religious practices surrounding death.