|Book(s)||The World of Ice and Fire (mentioned)|
During Aegon I Targaryen's conquest, Aegon was preparing to march on Dorne. But when he received word that Torrhen Stark was marching south with thirty thousand northmen at his back, Aegon led forty-five thousand troops to meet him at the Trident, and also his and his sisters' dragons, Balerion, Meraxes, and Vhagar. At the Trident, Torrhen took advice from his bannermen, while considering what had happened to Harrenhal and the Field of Fire. His bastard brother Brandon Snow offered to cross the Trident alone at night, to sneak into the Targaryen camp and assassinate the dragons while they slept. However, instead Torrhen sent Brandon and three maesters across the river to negotiate with Aegon, and the next day knelt and swore fealty.
A Dance with Dragons
Bran Stark has a vision of the past through Winterfell's heart tree. Among the visions is a pale, fierce, and dark-eyed young man, who slices three branches off the weirwood and shapes them into arrows. It is theorized that this may be Brandon Snow, preparing arrows to kill Aegon's three dragons.