How Bronzebeard and his friends/family from childhood gained their cutie marks.... Heroically of course! 'Cause everyone knows viking ponies earn their cutie marks heroically!
...EVERYONE
Well, maybe not all of them are heroic, but they all hold a great meaning nonetheless.

This is a little something I whipped up while I was bored. Eventually, I'm going to write some more stories about ol' Bronzy and the viking ponies... Also, this is my first time, so be gentle.
(The picture is a valknut, click the source for a definition)