|Red Keep, King's Landing
|Complete destruction of King's Landing with wildfire
After the rebel victory of Lord Robert Baratheon at the Battle of the Bells, King Aerys II Targaryen was fearful that Robert might actually win the War of the Usurper. The Mad King enlisted the aid of several members of the Alchemists' Guild in a plot to destroy the city of King's Landing should the rebel forces prove victorious. Ser Jaime Lannister was present when this was planned, while the rest of the Kingsguard was absent or with Crown Prince Rhaegar Targaryen.
Thousands of jars of wildfire were gathered and placed in key positions under King's Landing. Hundreds were placed under the Dragonpit and the Great Sept of Baelor, under every one of the city's gates, and even under the Red Keep itself. The pyromancers did their work in secret, and did not trust their apprentices with the knowledge.
The rest of House Targaryen were unaware of this; apparently Queen Rhaella Targaryen's eyes had long been shut to her husband's insanities, and Rhaegar was busy marshalling an army. The Hand of the King, Lord Qarlton Chelsted, grew suspicious of the constant comings and goings of the pyromancers from the Red Keep. When Chelsted discovered the plot, he confronted Aerys. When reasoning, threatening, jesting, and even begging on his part failed to dissuade Aerys from this course of action, Chelsted resigned his position, flinging his chain of office at Aerys's feet. Aerys had him burned alive for this, and made the pyromancer Rossart his new Hand of the King.
During the Sack of King's Landing, Aerys commanded Rossart to ignite the wildfire to destroy the city, and commanded Jaime to bring him the head of his father, Lord Tywin Lannister. However, Jaime intercepted and slew Rossart to prevent his message from reaching the other pyromancers. Jaime then slew Aerys, slitting his throat. A few days later, Jaime hunted down and killed Garigus and Belis, the other pyromancers involved in the plot.
A Clash of Kings
During the War of the Five Kings, Tyrion Lannister, acting Hand to King Joffrey I Baratheon, has the Alchemists' Guild prepare wildfire to defend King's Landing from an attack by King Stannis Baratheon. Wisdom Hallyne tells Tyrion that they have a great stock of wildfire from King Aerys's day, though much was lost after the deaths of the master pyromancers during the Sack. Hallyne says that recently two hundred jars were found in a storeroom under the Great Sept of Baelor, and nobody knew how they came to be there. Hallyne also tells Tyrion that wildfire grows more unstable as it ages, becoming explosive. Later, more than three hundred additional jars are found under the Dragonpit.
A Storm of Swords
The Dragonpit atop the hill of Rhaenys had been abandoned for a century and a half. He supposed it was as good a place as any to store wildfire, and better than most, but it would have been nice if the late Lord Rossart had told someone.—thoughts of Tyrion Lannister
The Targaryens never bury their dead, they burn them. Aerys meant to have the greatest funeral pyre of them all. Though if truth be told, I do not believe he truly expected to die. Like Aerion Brightfire before him, Aerys thought the fire would transform him... that he would rise again, reborn as a dragon, and turn all his enemies to ash.