When the egg hatched, Bahamut and Tiamat flew forth and spawned the first Dragons, banishing the the Ancient Ones and opening the Portals by which to escape to the 'Old World'. They left behind many Dragons to watch over the 'New World' and ensure the Ancient Ones never rise again. Their leader was a Gold Dragon among the very first generation spawned from Bahamut and Tiamat, known as the Primae Progeny, the Great Wyrm.
The Great Wyrm lived many centuries beyond a Dragon's typical life span, growing into a great beast whose wings spanned entire mountain ranges. But even time has its wear and tear on the king's mind. His reign oft can be described as a sleeping king 'sleep flying' while holding court in the skies.
Of course the divide between Chromatic and Metallic dragons easily grew as the Great Wyrm 'sleeping' grew longer and longer. A trickster and deceiver by the name of Livinyas, an Ancient White Dragon, gathered a following of Dragons and plotted to overthrow the Great Wyrm
Livinyas eventually staged a coup and launched an attack on one of the Great Wyrm's 'sleeping courts'. It was a suicide mission as the king's loyal followers flew to his defense, but champions of Livinyas armed with a dragon-slaying relic were able to fight their way through the fray and pierce the Great Wyrm's skull with the relic's blade, slaying the beast mid flight.
The Great Wyrm descended from the skies, crashing down upon the earth in a cataclysmic slam that levelled entire mountains. Though Livinyas and her rebels were quickly slain afterwards, their mission was complete. The Dragons leaderless, and thus scattered to the four winds to do as they pleased. Some held true to their watchful guardianship of the 'New World' like the ancestors of Rydess, others quickly squabbled and forgot about the task Bahamut and Tiamat bestowed upon Dragon-kind.
But where the bones of the Great Wyrm now rest has become a holy place of sorts for dragons in the 'new world, dubbed Wyrm's Fall. It has become a burial ground for all Dragons, young and old, mighty and small - a place where their remains may rest with their ancestors spirits. This is where Livinyas' spirit was reaching out from to contact Geld.