While The Chronicles of Narnia do not describe the Calormene religion in great detail, they offer a number of clues that give insight into the belief system:
- Tirian described his childhood visit to Tashbaan and noted that the temple of Tash contained a statue of the god.
- The Tisroc, the Calormene head of state, claimed descent from Tash, and Aravis Tarkeena mentioned that her father's family was "descended in a right line from the god Tash".
- Aravis described a ritual performed by Calormeme women in preparation of marriage: the bride-to-be would go into the wilderness and perform three days of ceremonial sacrifices to Zardeenah, as an indication that they were leaving the goddess' service when they married.
- It was mentioned that the calendar of the religion included an Autumn Feast (the time Aslan decreed that Prince Rabadash must stand in the temple of Tash to be cured of his donkey's form).
Based on this information, the Calormene religion seems to be a formalized belief system, with specific rules and rituals. Tirian's story illustrates two key points; that the religion had established centers of worship (at least within Tashbann), and that it made use of idols (at least of Tash).
Calormene religion also seems to be tied into the structure of the government (though it is unclear if that government could be considered a "theocracy" in the strictest sense of the word). While claims of descent from Tash may have simply been metaphorical (Calormene speech/storytelling is typically highly embellished), such ideas are rooted in reality: descent from the divine - or political authority granted by the divine - appear in several real-world cultures. Both concepts have been used by rulers throughout history to boost their status and prestige.
It has been widely speculated that C. S. Lewis was comparing the Calormene religion to Islam (though its followers, Muslims, are strict monotheists, not polytheists); Lewis, though, had also praised aspects of Islam in some of his works and the name "Aslan" means "lion" in the languages of many Muslim countries.