User blog comment:Zippertrain85/Dawnguard Follow up./@comment-17114085-20131216013719/@comment-17114085-20131216183747

"Harald was the first historic Nordic King. He was the first ruler to establish a centralized kingdom in Skyrim as it is known now"-from the Wiki, see Skyrim was divided until Harald came along and conquered it all and became the 1st High King(In 1E 143). I don't know exactly how Skyrim was ruled in between the Dragon Priest's fall and Harald's conquest but in that timespan its entirely possible Harkon was a noblema who rule part of Skyrim.