Historia de omnibus Gothorum Sueonumque regibus

The Historia de omnibus Gothorum Sueonumque regibus (History of all the kings of the Geats and the Swedes) is a posthumously published, partly pseudo-historical work by Johannes Magnus, Sweden's last Catholic archbishop.

[2] Already by this point, the Geatish population has grown to such an extent that the Scandinavian peninsula can no longer support them, and to solve this problem, Eric expels all rebels in his realm to isles in the west, where they become the Danes.

Over the next four hundred years, the amicable relations between Swedes and Geats deteriorate, and Johannes mentions the kings Uddo, Alo, Odin, Charles, Björn, and Gethar as rulers, of whom he writes that no knowledge has survived, save their names.

Concerned about how Finns, Curonians, and Ulmerugians have been raiding Sweden, Berig rallies the people for a war of conquest against the tribes across the Baltic Sea to seek vengeance and to regain the national honour.

Appointing his eldest son Humulphus to rule in his absence, Berig assembles a mighty fleet and sails to the isle called Gothiscandza by Jordanes, which Johannes identifies as Gotland.

Though the Ulmerguians put up a brave fight, they eventually realize that their forces are inferior to those of the Geats, and so burn their homes and fields and flee into "inner Vandalia".

These fictitious rulers were usually described in positive terms, but the invented King Gostagus (Ostanus, Östen III, number 90 in the list) is referred as a tyrant: "There was hardly a night throughout the year with him abstaining from fornication, rape, incest and the filthiest sexual intercourse".