The Gesta Danorum (Books I-IX) on Olmar
The Danish History, > Book Five.
attestation: All Russian kings except Olmar and Dag had fallen in battle
"all the kings of the Russians except Olmar and Dag had fallen in battle"
attestation: Olmar conquered Thor the Long, King of the Jemts and Helsings, plus Esthonia, Kurland, and Oland
"Olmar conquered Thor the Long, the King of the Jemts and the Helsings, with two other captains of no less power, and also took Esthonia and Kurland, with Oland"
attestation: Frode appointed governors: Olmar over Holmgard, Onef over Conogard, Hun over Saxony, Revil over the Orkneys
"he set Olmar over Holmgard; Onef over Conogard; and he bestowed Saxony on Hun, his prisoner, and gave Revil the Orkneys"