In William Beckford's Gothic novel Vathek, the caliph is named Vathek.
Vathek is portrayed as the ninth caliph of the Abbasid line, a ruler whose intelligence, wealth, sensual appetites, and hunger for forbidden knowledge drive the story. Beckford presents him as powerful but morally unstable, making him a classic Gothic protagonist whose ambition leads him toward supernatural catastrophe.
The novel begins with Vathek's encounter with a mysterious merchant who offers strange, magical objects. Pursuing the promise of hidden knowledge and immense power, Vathek becomes involved with occult forces and seeks access to the underground Palace of Fire, associated with Eblis. His quest requires increasingly terrible sacrifices and ultimately becomes a descent into damnation.
The name echoes al-Wathiq, a real ninth-century Abbasid caliph, but Beckford's character is a heavily fictionalized literary creation rather than a straightforward historical portrait. Vathek was written in French beginning in 1782 and first appeared in English in 1786 in a form that misleadingly presented it as an anonymous Arabic translation. The title is also commonly expanded as The History of the Caliph Vathek.