Short answers, pulled from the story.
The year 2600 BCE marks the estimated formation of Haplogroup I-Z63 according to genetic analysis by YFull. This calculation relies on volunteer samples from YDNA sequencing projects conducted in recent decades.
Researchers place the geographic origin of the progenitor within ancient Jutland. Current distribution patterns suggest a very high concentration of this DNA on the British Isles today.
A specific archaeological sample labeled CGG106524 provides physical evidence near Hjørring in Denmark. C14 dating places this individual's life between 400 and 220 BC during the pre-Roman Iron Age.
Foreign invaders displaced the original population explaining the relative lack of I-Z63 in modern Denmark today. The displacement caused by King Hacon likely pushed carriers toward other regions including the British Isles.
Sample VK157 from Bodzia Cemetery links to Sviatopolk the Accursed son of Vladimir the Great. Chester Arthur served as twenty-first president of the United States between 1829 and 1886 with lineage belonging to haplogroup I1-Z63 based on results from the Arthur family DNA project.