De origine actibusque Getarum (The Origin and Deeds of the Getae/Goths), or the Getica, written in Late Latin by Jordanes (or Jornandes) in 551, claims to be a summary of a voluminous account by Cassiodorus of the origin and history of the Gothic people, which may have had the title "Origo Gothica" and which is now lost. However, we cannot assess the extent to which Jordanes actually used the work of Cassiodorus (see the discussion below on the sources also used by Jordanes). It is significant as the only remaining contemporaneous resource, which gives the full story of the origin and history of the Goths. Another aspect of this work is its information about the early history and the customs of Slavs.

The Getica begins with a geography/ethnography of the North, especially of Scandza (16-24). He lets the history of the Goths commence with the emigration of Berig with three ships from Scandza to Gothiscandza (25, 94), in a distant past. In the pen of Jordanes (or Cassiodorus), Herodotus' Getian demi-god Zalmoxis becomes a king of the Goths (39). Jordanes tells how the Goths sacked "Troy and Ilium" just after they had recovered somewhat from the war with Agamemnon (108). They are also said to have encountered the Egyptian pharaoh Vesosis (47). The less fictional part of Jordanes' work begins when the Goths encounter Roman military forces in the 3rd century AD. The work concludes with the defeat of the Goths by the Byzantine general Belisarius. Jordanes concludes the work by stating that he writes to honour those who were victorious over the Goths after a history of 2030 years.