HBO released the much-anticipated Game of Thrones fourth season trailer on Jan. 12, eliciting equal parts confusion and unbridled excitement among fans.

It’s now common knowledge that the TV phenomenon is an adaptation of George R. R. Martin’s unfinished seven-part series, A Song of Ice and Fire, which he began writing in 1991. It’s since sold more than 24 million books worldwide.

Martin is under pressure from fans to finish the sixth and latest book installment, The Winds of Winter, which isn’t slated for release until at least 2015.

The franchise has spawned bobbleheads, beer, graphic novels, video games and card games — not to mention the hordes of fan fiction and trivia. While we need to wait and see who ends up on the Iron Throne, we've rounded up 15 lesser-known facts about the GoT series, its actors and Martin himself to tide us over.

Game of Thrones returns to HBO on Sunday, April 6.

Things You Didn't Know About 'Game of Thrones'