- "Let the earth gape! Let blood and fire obliterate the world! But be sure I will never desist till I have dragged to my palace by her hair the barbarian queen, the daughter of dogs, the __"
- ―Rabadash (Chapter 15) [src]
Though he could project a gentle and well-mannered persona, Rabadash was a cruel, evil, and tyrannical man who took delight in tormenting others. He was obsessed with his own pleasure, and had grandiose notions of his personal power. He had apparently acquired these traits through his upbringing in the decadent and wicked court of his father.
Despite being a grown man and the heir to the throne of Calormen, Rabadash was spoiled and rather childish, throwing tantrums when he didn't get what he wanted, and often making horrifying faces to terrify his inferiors (though it was implied that the latter was only effective because his inferiors knew that he could have them sentenced to death at a whim. When he tried the same tactic on the Narnian and Archenland kings, he merely looked silly).
This extremely self-centered focus prevented Rabadash from seeing the larger picture, and he was unable to make wise decisions when denied his desires. Instead, he mulishly continued to fight for his own way.
In the end, Rabadash's impotent rage and lack of self-control rendered him a laughing-stock, and gave him his later moniker, "Rabadash the Ridiculous".
During the Golden Age, the Monarchs of Narnia attempted to establish diplomatic relations with Calormen.
When he saw her, Prince Rabadash wanted to marry Queen Susan of Narnia, and courted her heavily during his time at Cair Paravel, as well as her and King Edmund's visit to Tashbaan. However, when she began to have doubts, he hinted that he might hold the Narnian delegation prisoners until she consented, or even outright force her to marry him. Fortunately, the Narnians were able to escape Tashbaan by night on board their ship.
Enraged, Rabadash demanded his father invade Narnia, but the Tisroc refused, as he feared the Pevensies because he believed they wielded powerful magic, due to the White Witch being slain.
Unwilling to give up, though, Rabadash conceived a plan to lead a raid to conquer Archenland, using 200 cavalries, and then use it as a staging post to later conquer Narnia and capture Susan.
During a secret meeting in the palace, he proposed this plan to his father, who consented on the condition that Rabadash pretend to carry the plan out as if in secret, and if he failed then he would be stripped of his birthright to inherit the throne. This meeting was overheard by two Tarkheena, one of whom was Aravis, who told her traveling partner, Shasta.
They crossed the desert, just ahead of Rabadash's raiding force, in time for Shasta to warn King Lune of Archenland, of the impending danger.
When Rabadash arrived at Anvard, an army of Narnians and Archenlanders were there waiting for him, ready for battle. They all fought in the Battle of Anvard, in which the Calormenes were defeated in a rather humiliating way.
Rabadash challenged King Edmund to a duel, but before he could even start, he had to jump off a wall to reach him, and the back of his hauberk (shirt of chainmail) got caught on a hook in the wall, leaving him to dangle there rather pathetically.
He still insisted on fighting Edmund, and demanded to be let down, but King Lune refused, saying that because of attacking Archenland in a time of peace, Rabadash had proven himself no knight, but a traitor, one rather to be whipped by the hangman than to be suffered to cross swords with any person of honour. Rabadash was then taken prisoner alongside the surviving Calormenes.
After the battle, Rabadash was brought to trial before the monarchs of Archenland and Narnia. During this time, Aslan appeared and confronted him about his aggression. He gave him able opportunity and chance for redemption and to accept the mercy that the Archenlanders were willing to show him, but Rabadash was unrepentant, and continued to bluster, threatening to never rest until he had Susan, even if he had to wage war on the entire world.
- "The hour has struck."
- ―Aslan (Chapter 15) [src]
As punishment, Aslan turned Rabadash into an ordinary dumb donkey, which would only be undone once he entered Tash's temple during his country's great Autumn Feast that year. Aslan then warned him that if he ever went more than ten miles away from the temple, he would resume his donkey form for the rest of his life.
After Aslan left, King Lune offered to transport Rabadash back to his home on his best cattle-boat, with the freshest of thistles and carrots, but his kind offer was, needless to say, refused with a rather hard kick from Rabadash to one of the Archenland guards.
Afterwards he returned to Tashbaan, where his people were celebrating the Autumn Feast in honor of Tash. When he stood on the altar of Tash in the great temple, in sight of all Tashbaan, he changed back into his natural human form, and everyone recognised him as their prince. Given that thousands witnessed this event, it was impossible for their government to hush it all up.
Eventually, he succeeded his father as the new Tisroc, but because of his curse he was unable to leave the city, which meant that he was unable to lead any military campaigns. Thus his reign was one of the most peaceful in Calormen's history, earning him the official title, "Rabadash the Peacemaker".
Behind his back, though, and after his death, due to his crushing defeat and transformation, he was referred to as "Rabadash the Ridiculous".
His reputation became very unpopular throughout the Calormene Empire, and if a student in a Calormene school ever did anything unusually stupid, they would very likely be called "a second Rabadash".
- Aslan changed Rabadash into a donkey because a male donkey is also known as a jackass, which is also another word for a stupid person.