Laudator Temporis Acti

Life of Wulfram, chapter 9, tr. Rob Meens, "With one foot in the font. The failed baptism of the Frisian king Radbod and the eighth century discussion about the fate of unbaptized forefathers," in Pádraic Moran and Immo Warntjes, edd., Early Medieval Ireland and Europe: Chronology, Contacts, Scholarship: A Festschrift for Dáibhí Ó Cróinín (Brepols: Turnhout, 2015), pp. 577-596 (at 579):

When the named King Radbod was to be immersed in order to receive baptism from the holy Bishop Wulfram, he hesitated and asked him (Wulfram), meanwhile binding him through an oath in the name of the Lord, where the greater part of the kings, princes, and nobles of the Frisian people were: in the celestial realm that Wulfram had promised him to be shown if he believed and would be baptized, or in that region that he called the Tartarus of damnation. Whereupon the blessed Wulfram responded: ‘Don’t be mistaken, glorious prince, there is a certain amount of the elect with God. For it is certain that your predecessors as princes of the people of the Frisians, who have departed without the sacrament of baptism, have received a sentence of damnation. But he who from this moment believes and is baptized, will enjoy eternal bliss with Christ.’ When the still pagan duke—pagan, because he was still on his way to the baptismal font—heard this, he, as they tell, withdrew his foot from the font declaring that he could not go without the company of his predecessors, the princes of the Frisians, to reside with a small number of the poor in that celestial kingdom.