Aegon Targaryen, nicknamed Egg in his youth, was the fourth son of a fourth son. He was called Aegon the Unlikely because he was unlikely to inherit the throne of the Seven Kingdoms. He is named king when a council bypasses those before him in the line of succession. Upon taking the throne, he became Aegon V. He ruled the Seven Kingdoms well, and his reign lasted more than twenty-five years. He perished in a fire at Summerhall, the Targaryen summer home. A young Aegon is one of the main characters in the Tales of Dunk and Egg novellas. In the HBO adaptation, Aegon is the father of Aerys the Mad King, rather than his grandfather. This change was made to simplify Maester Aemon’s relationship to the Targaryens.