Ligures, an ancient proto-celtic people of Italy, have horned helmet  
 
Example of ligurian helmet.

@northern haste  
@Joshua  
@Derplicious  
Sure but… but yaks do have horns. Like, the animal.  
 
Horns aren’t a part of a helmet. At least for yaks themselves. At least shouldn’t be.

@toonbat  
I believe it’s trying not to laugh.

@Background Pony #AA22  
By extension, though, I’d expect some vikings to wear horned helmets after having stolen them from someone else and gone ‘these look cool!’ - Vikings weren’t idiots, but they weren’t anywhere near ‘wise’ enough as a culture that you’ll convince me there wasn’t the occasional never-been-in-battle kid who thinks he’s a bad-ass when he joins the raiding parties or whatever.  
Though I guess the raid-leaders, or whatever you want to call them (just whoever would have authority over ‘proper battle-wear’) gave any youths dumb enough to wear those helmets a smack to the back of the head hard enough to knock the helmet off.  
So, maybe none of them got into a fight with them, even if I’d expect some horned helmets in their possession.

[deleted]

@ChuymaruZ  
I think they’re kind of a mix of different cultures associated with colder climates. Yikslurbertfest, for example, sounds rather Germanic.

@NaClO  
Japanese samurai (at least the high-ranking ones) used to wear some helmets with massive horns. Of course it helped mightily for those helmets to be visible in the hurly-burly of a battle.

@NaClO  
Pre-roman iberians hade “horned” helmets, they where in brons with extensions in the form of two “horns” in the upper front part of the helmets. They where probably used to intimidate the enemy, and probably hade no practical use beyond maybe ritual.

I doubt horned helms were historically accurate for any legitimate battle gear among humans. The horns would be a liability in battle.

Ok, I would like to know about historically accurate yak culture.

I’m not exactly sure what Rainbow Dash’s expression is meant to convey, and yet I empathize.

The only historical accuracy you need is that Vikings were BADASSES!!

I love how the yaks are a justified example of barbarians with horns.

Yaks many races to not offend any races.  
Yaks more sensitive for culture than buffaloes.

@ChuymaruZ  
they didn’t have horns either

@Joshua  
I thought yaks were mongolians

@Derplicious  
You’re right; the represent something Tibetan. I can tell by their decor.

@Joshua
 
Since when have the Yaks represented vikings?

What’s funny about this is it’s true; viking helmets don’t have horns.