This is a kind of FAQ about the Vikings, so please forgive me to provides with the cut and paste from the previous thread, Why didn’t news of Leif Erickson’s discovery spread across Europe?
+++
This is indeed one of FAQs on the Vikings. Please also check the following answers either by /u/sagathain, /u/Platypuskeeper, and myself in the following thread:
In short, the news reached also to Scandinavia, and out of Scandinavia in course of the 11th century. The oldest extant written account of Vinland was recorded in the late 11th century Germany.
Nevertheless, these points should be emphasized:
+++
I also wrote a summary about Leif in Can I hear about Leif Erikson, all I know about him is that he was the first important European to step foot in North America and I would like to hear about that and any other cool things he did?.
In short, Leif only appear in two medieval Icelandic sagas, put in writing more than 2 centuries after the original events (the exploration of Vinland) allegedly occurred. I don't say he was entirely invented by the later saga author(s) (there were probably some oral traditions on him also in the 13th and 14th century Iceland), but we are not sure whether he really played an important role in Vinland expedition as the later sagas claimed since the oldest written account of Vinland, transmitted and recorded in late 11th century Germany, does not allude to him at all.
As I briefly suggested in Is there any physical evidence of Leif Erickson's settlement on North America?, Leif became really popular (that means to have surpassed the fame of his father, Erik the Red (settler of Norse Greenland settlement)) first in post-medieval times, or it was not until the 19th century that his current popularity originated. His 'fame' of the first European to 'discover' Vinland belongs rather to post-medieval his afterlife to him as a real, historical figure.