It had been almost a decade since Gerion had sailed, when Lord Tywin heard news of the call to war.
Brandon Stark had challenged Rhaegar and been imprisoned; Lord Rickard had rode south, and he and his son had been cooked alive.
Consequently, the Mad King demanded Jon Arryn for the heads of his wards; and so Arryn revolted, and there began the division in the Seven Kingdoms.
Of course, Lord Tywin stayed on the sidelines. He had no greater reason not to be in the Mad King's employ, and only by Jaime being in the Kingsguard, could Tywin restrain a greater course of action against the Targaryen cause.
So he watched and waited, and heard of the Battle of the Bells and of the Trident; and at last, Lord Tywin rode with his westermen back down the goldroad where he had once left the capital in his rear.
Here he now sat upon his horse; treachery on his mind, relying on Pycelle to sway the king, where Varys surely must have his own mind.
The Lion Gate rose before him, and Lord Tywin tightened his grip on the reins of his horse; his army was well armored and well trained, provided for with the gold of Casterly Rock; the Mountain boomed commands in his black armor, and for Lord Tywin, the comeuppance would finally by his.
The shriek that shook the air stilled even the Mountain; Lord Tywin, so intent upon his wrath, drew out of his stupor, where all their eyes went to the sky.
Joanna.
So bright, so blazing and so big a creature burst from the sky, that by its dancing flames upon the city could all the soldiers hold back, in a sudden panic that Lord Tywin could not think fast enough, could not raise his hand with practised authority, could only register shock.
Jaime.
The dragon long gone for ten years swooped upon the city; flames lit beyond the Lion Gate, and though the gate was hurriedly raised, it was for soldiers to leave, and with good reason.
For green bursts of flames that spewed from the city began to spread, and Lord Tywin knew from the twist in his gut, that if not from the red or green flames, then it was by the dragon's cry that he knew who had suffered most.