How was Fridlevus II related to Halfdan?
Fridlevus II Fridleif (Ynglinga saga) was a son of Fróði of the Skjöldung (Scylding) lineage. In that work he was the brother of Halfdan and the father of Áli the Strong.
Sweyn Forkbeard Sweyn Forkbeard (Old Norse: "Sveinn Haraldsson tjúguskegg"; Danish: "Svend Tveskæg"; 960 – 3 February 1014) was king of Denmark during 986–1014.