That was a really fun movie, and it makes me want to read the book. The main character is an actual historical figure who may or may not have met the Vikings. He met a people that he had to work with, but kind of hated them. He complained about them in his writings a lot. The cleaning bowl scene was based on his complaints. The problem is, we don't actually know if those were the Vikings or another group. Since he was from South West Asia, he really didn't know or care that Europeans had different cultures. If it was the Scandinavian peoples, he has the most prolific information on them.

A big problem with Vikings is that it's all outsiders points of view. Even the Icelandic texts are from a century or so after, and was written more for entertainment than historical accuracy. We have some writings, but it's mostly small comments.

Here's the part people have a hard time understanding, even historians, the Vikings adapted to the cultures around them. We have their colonial housing in Canada, but coins have been found in the Southern US. Very likely the people who stayed married into the cultures there and disappeared. Could they arrive in the Mediterranean and even further south? Sure, but it wouldn't look like the Vikings you imagined. This is why it's so hard to figure out if that guy actually met them. BTW, his complaints were likely that of an aristocrat from a religiously run culture complaining that these people didn't follow his ceremonial washing and cleaning. By all other scores the Vikings were very clean. At one point Normans attacked Vikings because they were too good looking.