Faulty mememor and folk etymology strikes me again. Yes OE and ON are very similar.
Wikipedia:
Harald III Sigurdsson (1015 – September 25, 1066), later surnamed Harald Hardråde (Old Norse: Haraldr harðráði, roughly translated as "Harald stern council" or "hard ruler")
Since I'm at it might as well correct something else, not Trygrvvson, but Harold Sigurdsson!
Hello friends. Haraldr harðráði in old Icelandic means Harald Hard-buttocks. Yes, you've got that right. harðráði is a perjorative in some texts for a mean ruler and just as today it is in reference to a man's hind quarters.