The spear is a weapon which does not normally receive an excess of praise in Old Norse literature. Certainly, there are famed weapons like Gísli's Grásiða, or Óðinn's Gungnir, but on the whole it seems that, for most medieval Scandinavians, a spear was – to borrow from Oakeshott – just a spear. This, however, was not always the case and there is a particular type of spear mentioned in Old Norse sagas, the kesja, which deserves some attention. Kesjur are used in numerous engagements, both large and small-scale, in the sagas. Unlike other spears, the kesja forms part of a compound word – kesjulag – which appears to refer to a specific type of fighting during large battles. Just what kesjur were, and why they would have their own word for a specific type of combat, though, is uncertain.

The kesja appears in a large number of Old Norse texts – the Old Norse Prose Dictionary project at Copenhagen lists twenty-nine separate texts which reference the kesja, in genres ranging from contemporary sagas to romances and legendary sagas. It also occurs in Snorra-Edda, appearing in Þattur IV of Skáldskaparmál, the Spjóts heiti, which provides a list of alternate words to use for describing spears in poetry. Kesjur also appear in by-names, usually as an indicator of a particularly fierce warrior, as is the case with Harald kesja, son of Erik Ejegod, the Danish king at the start of the eleventh century.