In Tacitus' work Germania from the year 98, regnator omnium deus (god, ruler of all) was a deity worshipped by the Semnones tribe in a sacred grove.
Comparisons have been made between this reference and the poem Helgakviða Hundingsbana II, recorded in the 13th century from earlier traditional sources.
And of all their superstition, this is the drift and tendency; that from this place the nation drew their original, that here God, the supreme Governor of the world, resides, and that all things else whatsoever are subject to him and bound to obey him.
[1] The description is often compared with a prose paragraph in the Eddic poem Helgakviða Hundingsbana II where a place called Fjöturlundr (grove of fetters) is mentioned: Helgi obtained Sigrún, and they had sons.
[2] Due to the resemblance between the two texts, some scholars have identified the deity of the Semnones with an early form of Odin.