Who is the Calormene prince who attempts to marry Queen Susan?

The Calormene prince who attempts to marry Queen Susan is Prince Rabadash. He is the main antagonist of C. S. Lewis’s The Horse and His Boy and the eldest son of the Tisroc, Calormen’s ruler.

Rabadash visits Cair Paravel and courts Susan, but she discovers that he is proud, aggressive, and determined to possess her rather than respect her choice. When Susan escapes from Calormen, Rabadash persuades his father to let him lead a military raid against Archenland and Narnia. His plan is to capture Susan by force and seize a strategic route into Narnia.

The invasion fails when Shasta warns King Lune of Archenland. Rabadash is captured, and Aslan offers him a chance to repent. When he refuses, Aslan transforms him into a donkey. His human form is restored at the temple of Tash in Tashbaan, but he is forbidden to travel more than ten miles from the city. This makes his later reign peaceful, earning him the public title “Rabadash the Peacemaker” and the private nickname “Rabadash the Ridiculous.”