Lagertha’s Hairstyle in Vikings is super cool all the time. I guess you need bad-ass hair to be a shield maiden. Anyway, the side-braid is so hot right now, like the shaved side undercut that Natalie Dormer made look so hot, but without having to shave the side of your head. And Katheryn Winnick adds all kinds of flair and variations to the braids that makes her look like she is Viking royalty. Must have been nice to not have internet and smartphones so you can sit around and get your hair braided for hours every day.
If you like this kind of braided amazing hairstyle, you should also check out Octavia in The 100 and the other grounders hairstyles.