Wikipedia
Yngvar Harra (or Ingvar) Proto-Norse *Ingu-Hariz (d. early 7th century) was the son of Östen and reclaimed the Swedish throne for the House of Yngling after the Swedes had rebelled against Sölvi.
Snorri Sturluson relates in his Ynglinga saga that King Ingvar, Östen's son, was a great warrior who often spent time patrolling the shores of his kingdom fighting Danes and Estonian vikings (Víkingr frá Esthland). King Ingvar finally came to a peace agreement with the Danes and could take care of the Estonian vikings.
He consequently started pillaging in Estonia in retribution, and one summer he arrived at a place called Stein (see also Sveigder). The Estonians (sýslu kind) assembled a great army in the interior and attacked King Ingvar in a great battle. The Estonian forces were too powerful and Ingvar fell and the Swedish forces retreated. Ingvar was buried in a mound at a place called Stone or Hill fort (at Steini) on the shores of Estonia (Aðalsýsla).
Snorri then quotes a stanza from Þjóðólfr of Hvinir's Ynglingatal:
Þat stökk upp, at Yngvari Sýslu kind um sóat hafði, ok ljóshömum við lagar hjarta her Eistneskr at hilmi vá, ok austmarr jöfri sœnskum Gýmis ljóð at gamni kveðr.1 Certain it is the Estland foe The fair-haired Swedish king laid low. On Estland's strand, o'er Swedish graves, The East Sea sings her song of waves; King Yngvar's dirge is ocean's roar Resounding on the rock-ribbed shore.2The Historia Norwegiæ presents a Latin summary of Ynglingatal, older than Snorri's quotation (continuing after Eysteinn):
Hujus filius Ynguar, qui cognominatus est canutus, in expeditione occisus est in quadam insula Baltici maris, quæ ab indigenis Eysysla vocatur. Iste ergo genuit Broutonund, quem Sigwardus frater suus [...].
His son Yngvar, nicknamed the Hoary, was killed by the inhabitants while campaigning on an island in the Baltic called Ösel. Yngvar bred Braut-Ånund, whose brother, Sigurd, [...]
Ynglingatal only mentions the location Sysla (area paying tribute), Historia Norwegiae only mentions that he died during a campaign on the island Eycilla, i.e. Eysysla ( Ösel). In addition to his son Anund (Broutonund), it also adds second son named Sigvard.
Thorsteins saga Víkingssonar skips Ingvar's generation and makes his father Östen the father of Anund and grandfather of Ingjald. It adds a second son to Östen named Olaf, who was the king of Fjordane in Norway.
The name Ingvar is an Norse first name for males, common in Scandinavia, meaning protected by Ing (i.e. Freyr). Many notable Scandinavians have had this name, for example Ingvar Kamprad, and the legendary Swedish king Ingvar.
The feminine version is Inga.
The first element of the name is derived from Proto-Norse *Ing(w)ia (Ingi-), i.e. Yngvi, which was the original name of the god Freyr. The second element is probably either *Harjaz (warrior) or *Warjaz (defender). The name consequently either meant Freyr's warrior or Freyr's defender.
Igor ( rus. Igor', ukr. Ihor, bel. Ihar) is a given name derived from the Scandinavian name Ingvar, that was brought to ancient Rus' by the Vikings ( Ingvar or Yngvar). Igor ( Rurik's son) conquered Kiev. Old English sources suggest that the birthname of Ivar the Boneless might have been Ingvar, he is referred to as Hyngvar, Hingvar and Inguar in the English annals.