Dag the Wise
Dag the Wise or Dagr Spaka was a Swedish king of the House of Ynglings (dated to the 4th century by 16th-century historiographer Johannes Magnus). He was the son of Dyggvi, the former king. According to legend, he could understand the speech of birds and had a sparrow that gathered news for him from many lands. When the bird was killed on one of these trips, Dag invaded Reidgotaland (considering the date and location, apparently Gothiscandza), in order to avenge it. There he was ambushed by a thrall and killed. The earliest two versions based on  Ynglingatal, i.e. "Historia Norwegiæ" and "Íslendingabók" (see below) say that Dag was succeeded by his sons Alrekr and Eírikr who in their turn were succeeded by Dag's grandson Agne (in "Historia Norwegiæ" incorrectly called "Hogne"): "Historia Norwegiæ": "Íslendingabók" only lists the line of succession: "x Dyggvi. xi Dagr. xii Alrekr. xiii Agni. xiiii Yngvi"". However, in the "Ynglinga saga", Snorri Sturluson gives Agne as Dag's son and successor, and the two brothers Alrekr and Eiríkr as his grandsons. This is what Snorri tells of Dag: Then Snorri quoted "Ynglingatal" (9th century): The fact that "Skjótansvað"/"Vápnavað" appear both in  Ynglinga saga and in "Historia Norwegiæ"'s earlier summary of "Ynglingatal" but not in Snorri's later quotation from it, suggests that all of "Ynglingatal" was not presented by him.