And it even worked after dark!

In another argument against the barbarism of the Vikings, researchers have discovered that a small compass could have worked with other tools, such as a pair of crystals and a flat, wooden slab, to navigate when the sun was low in the sky or even below the horizon.

Study co-author Balázs Bernáth, of Eötvös Loránd University in Hungary, believes "the Vikings may have used a low-lying, domed object in the middle of the compass to create a wider, shorter shadow than a more typical sundial spike would. A wide hole within the center of the disk — previously interpreted as a place to grip the compass — could have served as a holding spot for this so-called central gnomon," allowing navigation after twilight.