IVAR the BONELESS was PRINCE IVAR (IGOR) of KIEV
I have just posted a first draft of Chapter 28 The Death of Ivar ‘the Boneless’ (Circa 944) to “The Saga of Ivar ‘the Boneless’ Hraerikson” Book of the website SeiberTeck.com under the Book Heading of that name.

The new chapter finds Prince Ivar sailing to Bardha with a war fleet to attack the militia army and their Roman trainers there. As the fleet beached upon the riverbank, the Hraes’ saw a great army coming down from the land before the city and one man was somewhat ahead of the host and he was waving the Hraes’ legion away. He had a sling and he took a projectile out of a pouch and slung it at Ivar and it landed at his feet. It was an apple, the fruit of healers. He slung another apple and it landed, again, at his feet. Then Ivar decided he wasn’t going to wait for the third apple: “There’s some kind of witchcraft behind this,” he shouted, and he grabbed one of the pig hunter’s bows and he shot an arrow at the apple slinger. The arrow hit the man on the nose and they heard a noise like snapping horn. He flung back his head, and they saw that he wore a hood with a large bird’s beak. He screamed very loud and ran back towards the army and suddenly the troops all broke and ran.
The above description is taken from the Swedish saga of Ingvar the Traveler and it is interesting that, even in that early period in history, the healer appears to be wearing the same bird beak plague mask that Nostradames and others wore during sixteenth century plagues. Here, the hard beak seems to have saved the doctor’s life and the troops were probably all sick with the plague and hoped that their numbers could frighten the enemy away. When Ivar responded with an arrow, they ran because they were likely in no condition to fight. Even in the tenth century, people knew to wear masks during pandemics.
The Varangians enter the city of Bardha without a fight and Prince Ivar takes over the palace of the satrap that had ruled there before fleeing the plague. He has left one of his sick concubines behind in the master suite and Ivar lets her recover in a corner of the huge master bedroom. The Hraes’ army goes out on raiding patrols looking for booty and Roman deserters. Over the winter months the young girl in his room seems to be slowly slipping away. Ivar catches the plague from her and panics and orders his army to leave Bardha in the middle of the night. They leave the city just before General Kourkouas is able to make a surprise attack upon the Varangians with a Roman army he has force marched from the Levant.
Prince Ivar is ill when he leaves Bardha and leads his men to the relative safety of the Caspian Sea. They sail north to the Kura River and attack the Khazar army guarding its mouth. Ivar falls in battle there but the Khazars stop fighting and tell the Varangians that he has died with no wounds. They do not want to be blamed for his death. Prince Hraerik studies Ivar’s body and accepts the Khazars story, but Ivar’s son, Prince Svein (Sviatoslav), would, decades later refute it and attack and crush the Khazar Empire in Book 4 of this series.
Book Three, “The Saga of Ivar ‘the Boneless’ Hraerikson,” reveals how Ivar the Boneless Ragnarson was actually Prince Eyfur/Ivar (Igor in Slavic) Hraerikson of Kiev and then King Harde Knute of Denmark. By comparing a twenty year lacuna in the reign of Prince Igor in the Russian Chronicles with a coinciding twenty year appearance of a King Harde Knute (Hard Knot) of Denmark in European Chronicles, Prince Igor’s ‘death by sprung trees’, which reportedly tore his legs off, may have rather just left him a boneless and very angry young king. Loyal Danes claimed, “It was a hard knot indeed that sprung those trees,” but his conquered English subjects, not being quite as polite, just called him, “Ivar the Boneless”.