In legend and in the early historiography of Switzerland there is an account of a migration of a population of Swedes and Frisians settling in the Swiss Alps, specifically in Schwyz and in Hasli (Schwedensage).
He gives an account of their decision to settle on the site of Schwyz:[2] Etterlin's account is supposedly based on a "common Swiss chronicle" (Gesta Suitensium, gemeine Schwyzerchronik) also reflected in the White Book of Sarnen, Heinrich von Gundelfingen (Das Herkommen der Schwyzer und Oberhasler[3]) and later by Aegidius Tschudi (Die Geschichte der Ostfriesen, Swedier und andre, so mit jnen gereisset, vnd wie Switer dem Lande den Namen Swiz gegeben).
[8] The saga is also reflected in early-16th-century Frisian chronicles such as the Tractatus Alvinus, Jancko Douwama's Boeck der Partijen and subsequent writings, as well as in the biography of the condottiere Wilwolt von Schaumberg from Thuringia, who led the conquest of Frisia by Albert of Saxony in 1498.
In Sweden, Uppsala historian Jakob Ek published an account of the legend in De Colonia Suecorum in Helvetiam egressa (1797).
[12] Erik Gustaf Geijer in his History of the Swedes (1832–36) notes that the legend was now limited to the population of Haslidale but had once also been generally believed by the people of Schwyz.
In this version, the Swedes march from a place called Hasle on the banks of the Rhine, defeating a Frankish army on the way, and settle in the alpine valleys because the landscape reminded them of their own country.
Geijer equates this expedition with one mentioned in Óláfs saga Tryggvasonar, in which the sons of Ragnar Lodbrok participated, advancing as far as Wiflisburg (Avenches) in Switzerland.