This meme is shared on Facebook. It claims that “Harald Fairhair is often conseidered the first Viking King”
Haraldr hárfagri (Harald Hårfagre/ Harold Fairhair)is a legendary king of Norway. In the later Icelandic sagas he is said to have unified Norway in around 871 as the meme says. If it is true, we do not know, but since the sagas are written 500 years later, they are not a reliable source for this. Many historians doesn’t think that Harald Farhair became king of all of Norway.
This is not the part of the meme that will talk about here though. The meme claim that he is the first “Viking King”. If we look away from the meaning of Viking as a pirate and just understand the claim as “The First Scandinavian King from the Viking Age”, the claim is still wrong.
The Frankish annals that are written down at the time they rite about and therefore are much more reliable than the Icelandic sources has many Danish kings before year 871.
The oldest one is Sigfred in year 777, Godfred is king around year 800, He is followed by his brothers son Hemming was king in 810, Harald Klak is made king in Denmark by the franks around 814 (ruled together with some of Godfreds sons), Horik the first is king from 813-854.
Sources:
https://lex.dk/Harald_H%C3%A5rfager
https://danmarkshistorien.dk/perioder/vikingetiden-790-1050/kongelig-politik