With the help of his giant dragons, Aegon the Conqueror invades, subdues, and unites six of the seven kingdoms of Westeros under his banner and constructs a new capital city at King's Landing. He is unable to conquer Dorne and allows it to remain sovereign.
The first major civil war in the history of the Seven Kingdoms was a war of succession between Aegon II and his half-sister Rhaenyra Targaryen over their father's throne. Known as the "Dance of the Dragons," it consumes them both, as well as most of the Targaryen family and their remaining dragons. The war ends with Aegon III, son of Rhaenyra, being crowned. King Aegon Targaryen is unable to prevent the death of the last dragon, earning himself the title "Dragonbane." The last dragons leave behind several eggs which the Targaryens fail to hatch. These eggs are later destroyed or lost, leaving many to believe the dragons extinct. Aerys II reigns as the Mad King in 262 AL. He appoints the ruthless young Tywin Lannister as his Hand. To add insult, King Aerys spurns Tywin's offer of his daughter Cersei for Prince Rhaegar, and instead marries Rhaegar to Princess Elia Martell of Dorne.