What does Game of Thrones and History of the Kings of Britain have in common?

So the obvious answer is dragons right. Wrong. At least for my post it is. Sigils are the answer to my hard hitting question. They are the icon of the family and they have been around for many a year. They are the identifying picture that can tell a person who your family is, who you ally with, or even where you're from. 

As mentioned, sigils have been around for a long time and being that George R.R. Martin pulls from history itself, I figured why not look into it. So I did and I found this awesome Game of Thrones picture of the main houses and their sigils. 

So this has excluded some of the main ones, like House Stark and Targaryen, but most of the others are here in this picture. This goes along with this fantastic blog I read here*. It has this chart of about what possibly inspired the sigils for the GoT houses, like House Targaryen and the red 3-headed dragon as their sigil is inspired by King Arthur and Merlin the dragonlord.

In History of the Kings of Britain, Merlin has a prophecy about the red and white dragons and Arthur’s family symbol is the almighty dragon. As the sign of this family, the dragon image has solidified the stories of King Arthur being so powerful much like his father Uther. So, much like Henry Tudor, who claimed to be a descendant of King Arthur to help strengthen his claim to the throne, the use of the dragon symbol aids Daenerys in her claim to the throne because of the power that comes with it.  No one is going to willingly fight a dragon, and as seen throughout the lore, dragons strike fear into those brave enough to look upon it.

*the chart mentioned in the blog post is the imaginings and thoughts of what might be the inspiration of the sigils for the show. None of the explanations were confirmed by Martin.