The Vegvisir ("way-shower") is known from the Huld manuscript, a collection of Icelandic magic compiled by Geir Vigfússon in 1860. The accompanying text says that whoever carries the sign will not lose their way in storms or bad weather, even when the way is unknown.
It belongs to a rich Icelandic tradition of galdrastafir, magical staves drawn for protection, luck and safe travel. No Vegvisir has been found on any Viking Age object, and the nickname "Viking compass" is modern. It became widely known in the last few decades, and today it is one of the most popular Norse tattoo designs in the world.