The Gesta Danorum (Books I-IX) on Hogni
The Danish History, > Book Five.
attestation: Hogni betrothed his daughter Hilda to Hedin, and they swore mutual oaths of vengeance
"Hogni betrothed his daughter to Hedin, after they had sworn to one another that whichever of them should perish by the sword should be avenged by the other"
attestation: Hogni attacked Hedin's fleet while he was collecting royal dues among the Slavs, but was defeated
"the credulous ears of Hogni drank in this lying report, and with his fleet he attacked Hedin, who was collecting the king's dues among the Slavs; there was an engagement, and Hogni was beaten"
attestation: Hogni spared the wounded Hedin in combat, deeming it shameful to kill a youth at his last gasp
"though Hogni had an easy chance of killing him, yet, pitying youth and beauty, he constrained his cruelty to give way to clemency"