We know that about 489 the Eruli were just north of the Danube, and were the Goths' nearest neighbours. Now, as we shall see later, Eruli was perhaps at first a common name for bands of northern warriors, and these Eruli on the Danube may therefore certainly have consisted to a greater or less extent of Norwegians. We know, further, that at this time there was a king of the Eruli to whom Theodoric sent as a gift a horse, sword and shield, thereby making him his foster-son [cf. Cassiodorus, Varia iii. 3, iv. 2]. Finally, we know from Procopius that the Eruli just at this time had a king, Rodulf, who fell in battle against the Langobards (about 493). When we compare this with what Jordanes says about the Norwegian king Rodulf, who hastened to Theodoric's arms and found there what he sought, it will be easy to conclude that this Norwegian chief is the same as the chief of Eruli here spoken of. Rodulf, or "Hrodulfr," is a known Norwegian name. "Rod-," or "Hrod," is the same as the modern Norwegian "ros" (i.e., praise), and means probably here renowned.
One is further inclined to believe that it was from this Rodulf or his men, of whom some may have come from And in Hålogaland, that Cassiodorus or his authority obtained the information about Scandinavia and northern Norway, which is also partly repeated in Procopius.
Sophus Bugge [cf. 1910, pp. 87 ff.; see also A. Bugge, 1906, pp. 35 f.] has suggested that the "Ráðulfr," who is mentioned in the runic inscription on the celebrated Rök-stone in Östergötland (of about the year 900), in which Theodoric ("Þiaurikr") is also mentioned, may be the same Norwegian chief Rodulf who came to Theodoric and who fell in battle with the Langobards. He even regards it as possible that it is an echo of this battle which is found in the inscription, where it is said that "twenty kings lie slain on the field"; in that case the battle has been moved north from the Danube to "Siulunt" (i.e., Sealand). There are other circumstances which agree with this: it is said of the Eruli that they had peace for three years before the battle [cf. Procopius]; on the Rök-stone it is stated that the twenty kings stayed in Siulunt four winters; the latter must have been Norwegian warriors of different tribes: Ryger, Horder, and Heiner (from Hedemarken), perhaps under a paramount king Ráðulfr, who settled in Sealand--while the Eruli were bands of northern warriors, who under a king Rodulf had established themselves on the north bank of the Danube. Bugge's supposition may be uncertain, but if it be correct it greatly strengthens the view (see p. 145) that the Eruli were largely Norwegian warriors, since in that case the king of the Eruli, Rodulf (== Ráðulfr), would have been in command of tribes for the most part Norwegian: Ryger, Horder, and Heiner.