UAPB GOLDEN LIONS!!!
Back then that behavior was normal lol. I definitely agree this show is the best thing going. I'm looking forward to the many different prequels they come up with. That should clear a lot of our questions up about the identity of the night king etc
Incest was common amongst House Targaryen, but I don’t think it was with the Lannister’s. While Tywin Lannnister did marry his cousin, I don’t believe any of the Lannister’s had relations between brother & sister.....until Cersei & Jamie came along. Lady Joanna, mother to Cersei, Jamie, and Tyrion, first caught Cersei & Jamie together when they were young forbade them from doing it again. She tried to keep them separated as best as she could. She also kept that from Tywin. Cersei did have a sexual relationship with her cousin Lancel.
The book suggests that incest wasn’t common for The Lannister’s but I may have read it wrong.