Árvakr and Alsviðr

In Old Norse mythic cosmology the gods (the Æsir) set the Sun in a chariot (Álfröðull / Sól) which is driven across the sky; two named horses, Árvakr and Alsviðr, literally draw that chariot each day. The Æsir arranged protective measures—cool iron (ísarnkol) hidden under the horses' shoulders—to enable them to endure the Sun's heat. Textual tradition places this daily labor within a larger eschatological narrative in which the wolf Sköll pursues and is fated to overtake and devour the Sun at Ragnarök.

The sources identify them as horses and describe them in at least one poetic rendering as "slender horses." Beyond their identification as horses and these adjectival epithets, the supplied texts provide no detailed color, size, or further anatomical description.

Their primary function, as given in Grímnismál and related summaries, is cosmological and instrumental: Árvakr and Alsviðr pull the Sun's chariot across the sky daily. Alsviðr's name and poetic epithets emphasize great swiftness; Árvakr's name evokes early rising or waking, fitting the horses' role at dawn. The Æsir's placement of cool iron under their shoulders is described as a measure to help them endure the Sun's heat. Despite their endurance and speed, the tradition records that the Sun (and by extension its chariot and horses) will be pursued and ultimately caught and devoured by the wolf Sköll at Ragnarök.