No one, not even the greatest greenseers had foreseen the Doom of Valyria.
And who could blame them; the idea of the greatest empire in human history all but vanishing in the course of a single day was inconceivable unthinkable.
And yet it happened; where once the proud cities of the freehold stood in the Fourteen fires, there was now an oppressive ominous permanent curtain of smoke that covered what was once the core territory of the Freehold, once a peninsula now separated from the rest of the continent. To everyone afterward, it would seem as if the great empire had never existed. No one knows how this catastrophe came to be and with every expedition to the lands of always summer disappearing without a trace, no one wants to find out.
Though the Doom happened in an eyeblink, its aftereffects had lasted for nearly a century as with the fall of Valyria, the order they had imposed on Essos collapsed as each of the free cities began to war amongst themselves, seeking to fill the power vacuum.
Volantis was the most successful among them, achieving hegemony for a while until Tyrosh began to challenge them which led to a cascade of events that saw every other city save for Lorath arrayed against them.
With all of Essos against them and the Dothraki beginning to encroach on their borders, all hope seemed lost for as they steadily began to lose on all fronts when dragons were spotted overhead.
Aegon Targaryen and his two sisters arrived with an offer to the desperate Volantenes, accept him as their new ruler and become the capital of a new Valyrian empire and he will deliver victory to them.
Though the choice seems obvious, the Triarchs hesitated; this would go against the traditions of the city and risked the populace rioting but Aegon's rhetoric was persuasive and appealed to the Tigers' martial spirits (and the presence of his enormous dragon certainly played a role).
Eventually, they relented and soon Aegon was crowned as the emperor of the newly christened Targaryen Freehold. He did not have much time to savor his victory however as he now faced the might of seven cities.
He first smashed Myrish-Lysseni-Tyroshi armies utterly in a apocalyptic battle in the Disputed Lands in which the armies of the three sisters were all but annihilated leaving the cities' defenseless especially when the Bravos abandoned them to their fates (a fact they would not forget in the years to come). Though some continued to resist the Targaryens, most were smart enough to yield and thus the greatest power block to rival Aegon's was subdued and added to his growing empire.
Afterward, Qohor and Norvos surrendered after their fleets were burned to ashes in the battle of Red sails by Visenya and her dragon Vahgar.
Lorath also pledged fealty to the new empire when Rhaneys and her dragon arrived at their doorstep though they remained as non-committing about it as always and stayed aloof of the overall conflict.
Afterward, she flew to Pentos where with careful diplomacy she managed to win over the Pentosi Magisters without bloodshed.
All the while Orys Baratheon, the rumored half brother to the emperor was sent under a host of some fifty thousand men to put an end to the Dothraki threat and add the lost daughters of Valyria, Tolos, Mantarys, and Elyria into the fold which he did successfully despite intense resistance from the Horselords, in the process also gaining the allegiance of the last Sarnori cities.
Andalos its petty kingdoms fractious as always were easily conquered.
By now Aegon controlled most of Essos, a realm only rivaled by that of Yi-Ti with only Bravos remaining free from the Dragonlords' control, for though Aegon and his sisters were fierce warriors and dragon riders, even they did not dare provoke the Bravosi into unleashing the Faceless men on them for while dragons could protect one from even the mightiest of armies, they were useless against a knife in the night.
And so the Bastard daughter of Valyria was spared from Dragonfire.
Though Aegon had succeeded in doing the impossible and reuniting the formerly Free cities into one empire, he would soon come to realize that conquest was the easy part, it was the challenges of ruling such a vast domain that would truly test him, especially since many still chaffed at the thought of being subjected after being free for so long.
The century of Blood and the subsequent rise of the Targaryen Freehold went by mostly unnoticed by the Westerosi other than some troubles with the Vlayrian trading outposts that remained in the North, most notably a rogue Dragon rider who traveled Beyond the Wall seeking to forge an empire of his own among the Wildings.
He would never be seen again.