Daeron II was married to Princess Mariah Martell, officially bringing Dorne under the rule of the Iron Throne. had four sons, his oldest was Baelor “Brakespear.” Baelor had already established himself as a war hero during the Blackfyre Rebellion but he was also a thoughtful man who valued honor and fairness. In short, everything you’d want in a king. So naturally, he died young. During a tournament he took a blow to the head, and while his helmet saved him, he soon succumbed to his wound.
Not long after, Westeros was hit by a nasty plague. Many died, including King Daeron, and Baelor’s two sons. This meant the throne passed to the second son Aerys I. Aerys was an intellectual like his father and spent most of his time reading and studying. Unlike his father, he lacked any real resolve or interest in ruling (he rarely ever wore his crown.) He appointed Bloodraven as his Hand and let him rule. During his reign both the Blackfyres and the Greyjoys rebelled against the throne.
Aerys died childless and his younger brother Rhaegel and nephew Aelor both died soon after. So Maekar, the youngest son became king. Proud, envious and angry, Maekar always had a chip on his shoulder. He fought alongside Baelor against the Blackfyres but never received the renown and adoration his older brother did. And in an unfortunate turn of events, it was Maekar who accidentally killed Baelor during the tournament. While his reign was a peaceful one, Maekar lived the rest of his life deeply troubled as he could never shake his reputation as a kinslayer.