After defeating a dozen castles in the vicinity of Blackwater Bay, Aegon Targaryen commanded the defeated lords to attend him at the Aegonfort atop what would become known as Aegon's High Hill. There, the lords laid their swords at the conqueror's feet, and he confirmed them in their lands and titles.
The city of King's Landing formed around the Aegonfort, the seat from which Aegon himself ruled. The Aegonfort itself grew larger as well, and would come to emcompass more of Aegon's High Hill. A new wooden keep was raised, with walls fifty feet high. The Aegonfort stood until 35 AC, when Aegon tore it down to raise the Red Keep, a castle fit for the Targaryens.