Aegon I Targaryen

Aegon I Targaryen, known as Aegon the Conqueror, is a historical character referenced in Game of Thrones. He is long dead by the time of the series and is not expected to appear.

Aegon I Targaryen was the first king of the Targaryen dynasty. He is the king who invaded and unified the Seven Kingdoms of Westeros, founded the city of King's Landing, built the Red Keep and forged the Iron Throne.

In the books
In the Song of Ice and Fire novels, Aegon was a child of House Targaryen, dwelling on the island of Dragonstone in forced exile following the Doom of Valyria, the destruction of their homeland. When he was of age, Aegon and his three dragons led a scant few thousand troops in invading the entire continent of Westeros. Despite being vastly outnumbered, Aegon was able to secure victory after victory using his dragons. He smashed the Tyrell and Lannister armies on the Field of Fire, securing their capitulation, and convinced the Arryns and Starks to join him peacefully through negotiation. Eventually all of Westeros acknowledged him as king, save only Dorne which he decided not to conquer after encountering tough resistance.

After the Conquest, Aegon ruled for thirty more years, apparently wisely and well. However, upon his death the realm was plunged into a bloody war when the Faith of the Seven rejected his sons, born of incest, from following him on the throne. Eventually the uprising was put down and the Targaryen rule secured for centuries.