His name was absolutely not "Magnus I Ericsson Nilssøn af Danmark (Estridsøn), kung av Sverige".
Here are the correct name in different languages:
https://en.wikipedia.org/wiki/Magnus_I_of_Sweden
https://sv.wikipedia.org/wiki/Magnus_Nilsson_(kung)
https://da.wikipedia.org/wiki/Magnus_den_St%C3%A6rke
https://no.wikipedia.org/wiki/Magnus_den_sterke
https://de.wikipedia.org/wiki/Magnus_%28Schweden%29