An Excerpt from The Annals of the Green Triumph, penned by Archmaester Vaelor in the Reign of King Aegon II Targaryen
"Of wars unlooked for, it is said: Fortune's wheel turns swiftest when pride and grievance compel great powers to folly."
It was in the waning days of that fateful year—under the last moon, as the snows began to drift upon the Crownlands—that envoys from the lagoon city of Braavos passed beneath the shadow of Maegor's Holdfast. Robed in the austere greys and violets of their order, they entered the Red Keep as men accustomed to power and unafraid to show it, bowing shallowly—some claimed insolently—before the Iron Throne.
Their words were plain, if not impudent. The Sealord of Braavos, in his infinite grace, urged the Crown to acknowledge the rightful claim of Princess Rhaenyra Targaryen—dispossessing the Iron Throne—or else face the Titan's wrath.
It is said that Prince Aemond Targaryen, the Butcher Prince, stood at the foot of the throne that day, silent and still as a statue of old Valyria. He listened to the Sealord's envoys speak their peace, and said nothing in reply. That night, their heads were found aboard a galley bound back to Braavos, the bodies never recovered.
Pinned to one of the heads was a message, inked in Aemond's own hand:
"Your masters, in their wisdom, have allowed you to play at liberty, content to watch as you squander their indulgence on trifles. Yet now, unbidden, you reach beyond your grasp, meddling in affairs far beyond your lowly station. Perhaps the hour has come for the bastard daughter to be reminded of her place beneath the yoke."
—Aemond Targaryen
The response in Braavos was swift and furious. To slay envoys was an affront to the oldest customs of peace among the Free Cities, and Aemond's letter—veiled as it was in rhetoric—was an insult to the very essence of Braavos's existence. In the Palace of Truth and the counting halls, the cry went up: War! Only then was it apparent to those few voices of reason that perhaps a peaceful reconciliation was truly now a foregone matter.
Yet in Westeros, the demands of the Titan had stirred a new anger. With House Velaryon's sea-power largely under the Crown's aegis (through Lord Corlys Velaryon, who had proven staunchly loyal to the Crown), and Houses Hightower, Lannister, Arryn, Redwyn, Tully and Stark newly ascendant under a new reign, the mightiest lords had no further appetite for Essosi impudence.
Rhaenyra's remaining few supporters—those not dead, exiled, or cowed—found no refuge now in Westeros, for her retreat to Braavos had tarred her as a tool of foreign powers. Lords who once might have quietly harbored Black sympathies realized the kingdom's enmity was fixed on Braavos alone; to stand with Rhaenyra anew was to join a cause that the Butcher Prince had vowed to crush.
Thus, decrees were issued from the Red Keep: any harbor that welcomed Braavosi trade would be judged traitor. A flurry of envoys crossed the sea lanes to Pentos, Myr, Lys, Tyrosh, Lorath, and even Norvos each one carrying letters sealed with the Three-Headed Dragon of Targaryen, warning those city-states not to entangle themselves in Braavos's folly. At home, the words "Enyoke the Bastard Daughter" became a refrain. Old rivals set aside grudges to answer the Crown's muster.
...
In the shipyards of Oldtown, Lannisport, Gulltown, and White Harbor, masts rose like forests of oak and pine. The Royal Fleet—numbering in the mere dozens—saw its ranks swelled to the thousands by privateer galleys and merchantmen crafts. From across the realm, the great fleets gathered: House Redwyne's storied wine ships were refitted with scorpions; House Lannister's bright-lacquered carracks carried steel-tipped rams. Even modest ports from the Sunset Sea, and as far east as Qarth, hammered Hightower cogs and caravels into warships.
The realm's armies, yet relieved from the musters of Dance, were reformed under new standards. Lords from the Riverlands, Reach, Westerlands, and even the previously lethargic North answered the King's call, each raising fresh levies in the tens of thousands to add to an already grand host. True, those swords could serve only if Braavos dared land troops on Westerosi shores—or if Westeros itself meant to cross the Narrow Sea. But rumours had it that the King desired to show no weakness.
Above all, the Crown prized its dragons. All nine of them: the monstrous Vhagar, still formidable despite her age; Vermithor, Silverwing, Seasmoke and Sheepstealer, newly claimed by Aemond's handpicked riders; Sunfyre, the noblest of all; Dreamfyre, the regal mount of Queen Helaena; Meleys, the Red Queen, Tessarion, the Blue; and the petite, Moondancer—small but agile. None could deny that Westeros's aerial supremacy was more than assured.
Meanwhile, across the Narrow Sea, Braavos channeled the fervor of its storied past. In the famed Arsenal, fires glowed day and night as oarsmen and shipwrights toiled to birth more war galleys to match Westeros' swiftly growing navy. The city's labyrinthine canals bobbed with new ships: sturdy dromonds armed with bolt-throwers and cunning nets said to be capable of hampering even the greatest of dragons.
...
In the end, all recognized that the Stepstones would become the crucible of conflict.
Scattered and sun-blasted though they were, the isles had long held outsize importance in the balance of power across the Narrow Sea. Now, with Prince Aemond Targaryen's grip tightening like a mailed fist about their coasts, the lanes that once flowed freely with Braavosi goods ran dry. Trade with the southern ports of Essos was hindered, and the Titan, ever jealous of its merchant primacy, would suffer such indignity no longer.
And so, with fire smoldering behind their outward calm mein, the Sealord's court dispatched a host of warships to Tyrosh. Some claim as many as four thousand galleys bore the Braavosi pennants; others, more sober-minded, place the number nearer twenty-two hundred. Regardless, the intent was plain: to rally the sellsails of the southern seas, test the mettle of the Westerosi defense, and perhaps succeed where the Queen's own forces had once faltered.
Alas, King Aegon—with cunning counsel from his Master of War—had long reinforced the isles. Watchtowers rose upon the hills, and fortresses bristled with scorpions and catapults. Garrisons had swelled fivefold, and the patrols prowling the narrow straits by day and night had tripled in number over mere moons. Some smallfolk whispered that Aemond himself had flown Vhagar above the islands more than once, though whether this was truth or rumor none could say.
For the moment, the Braavosi schemed cautiously. Their admirals recalled too well the bitter cost of Rhaenyra's earlier forays—how the isles had swallowed coin and life alike. They tested the defenses in feints and skirmishes, probing for weakness, but the Crown's lines held fast.
Both sides knew the stakes. One reckless assault, too soon or ill-coordinated, might shatter the Braavosi host. Yet one lapse in the defense—a fort undermanned, a convoy caught adrift—could unravel the carefully laid blockade.
Thus the Stepstones brooded beneath storm-laced skies, a tinderbox where fire might be struck at any hour. And all who watched from afar understood: a great war was about to begin in earnest.