The fourth son of a fourth son, Aegon was called "the Unlikely," and became king only after a Great Council that bypassed a number of candidates earlier in the line of succession, and after his elder brother Aemon refused the throne. He was a strong and handsome man, but also friendly and approachable and ruled Westeros well as king for over a quarter of a century.

As a child Aegon traveled the countryside of Westeros as "Egg," squire to the hedge knight Ser Duncan the Tall, more commonly known as "Dunk". Aegon at the age of ten first meet and befriended Dunk on a chance meeting at an inn where Egg and his older brother Daeron were staying. After the Ashford tournament Egg pleaded with his father Maekar to let him serve as Dunk's squire. Prince Maekar agreed, hoping that living humbly with an honorable hedge knight such as Dunk for a few years would turn Egg into a better man than his brothers, Daeron and Aerion. After Egg was crowned, he made Ser Duncan commander of the Kingsguard and even named his firstborn son after Duncan in honor. Their adventures together are the subject of the "Dunk and Egg" short stories. The last of the Blackfyre pretenders died in his reign during the War of the Ninepenny Kings.

Aegon perished in a fire at Summerhall, the Targaryen summer home. Aegon's son, Prince Duncan the Small, and Dunk himself also perished in the incident.

From "A Song of Ice and Fire" by George R R Martin