What is "calormen"

In C. S. Lewis's Chronicles of Narnia series of novels, Calormen is a large country to the southeast of Narnia. Lewis derived its name from the Latin calor, meaning "heat". When using the name as an adjective or an ethnonym, Lewis spelled the name with an 'e' at the end: a Calormene soldier; "The Calormenes have dark faces and long beards." Narnia and Calormen are separated by the country of Archenland and a large desert. In The Horse and His Boy Calormen is described as being many times the size of its northern neighbours, and it is implied that its army is always either conquering more land or keeping down rebellions, in wars with which neither Narnia or Archenland are involved. The border of the Calormene Empire extends from the Western Mountains to the Great Eastern Ocean. The Calormene capital city is Tashbaan, a vast, walled metropolis near the northern desert separating Calormen from its northern neighbors, located near the mouth of the Calormen River.