Description of this motif: One can find several priests in Andersen's tales, but they seldomly play important roles. "A Story" (1851) stars a priest, though.
Holger Danske gave Prester John his power and rule over India.
Comment on this quote: According to the commentary in H.C. Andersens eventyr, vol. 7, DSL/Borgen, Copenhagen 1990, p. 250: Prester John, Jon Præst or Johannes Presbyter was a medieval legend. According to folklore he ruled over a great and powerful kingdom in Asia. The legends of Johannes Presbyter are collected in the Danish popular book Jon Præst, published by Christiern Pedersen 1510 (most recent ed. by Allan Karker 1978); according to one of these legends J. P. was a Frisian king's son, who followed Holger Danske on his cruise to Asia. After having conquered India Holger Danske installed J. P. as the emperor of all Indian countries.