It is amazing that we share this world with people like Snoop Dogg, who believes Game of Thrones is "true history". What a time to be alive, yeah? But don't jump into the let's-laugh-at-Snoop-Dogg bandwagon just yet. Did you know that if you leave out the dragons, the red priests, the white walkers and other magical beings, the base plot revolving around the power struggle in Westeros is actually based on an actual part of British history? The War of the Roses (14th and 15th century) was not just a set of military campaigns but a slew of strategic alliances and betrayals between families and power-players, just like the backbone of George R.R. Martin's A Song of Ice and Fire series.
Here's a video that explains it better.
Source - TED-Ed