Aegon the Conqueror invaded Westeros around -2 AC and managed to overthrow most of the Seven Kingdoms pretty quickly, establishing his capital in King’s Landing. Using three dragons to secure his reign, he melted the weapons of his enemies after winning into the Iron Throne ; the throne that would later be fought over fiercely.
How HBO's new Game of Thrones spin-off A Knight of the Seven Kingdoms: The Hedge Knight could further trace back to all that Targaryen genealogy you spent so long learning.
Game of Thrones consists of three main story arcs: the struggle between the Lannisters and the other major houses of Westeros for control of the Seven Kingdoms of Westeros; the return of Daenerys Targaryen from Essos to reclaim the throne of her father, former King of the Seven Kingdoms; and the growing threat in the north of the White Walkers