 The letter was made during the time of Cassiodorus's public service in the early 6th century, and is dated to 507-511.More speculatively, another debated issue is whether Rodulf could be the inspiration for certain aspects of later heroic poetry, possibly including the Norse saga character Hrólfr Kraki.The Herul kingdom was centred on Lower Austria and Moravia, north of the Middle Danube.