Hiero's journey : a romance of the future

Blurb

Hiero's Journey is a post-apocalyptic science fiction novel by American writer Sterling Lanier first published in 1973. The novel follows the adventures of a priest by the name of Per Hiero Desteen as he explores the mutant-infested wilderness of Canada and North America five millennia after an event called The Death destroyed civilization. Riding a mutant moose named Klootz, with which he is able to communicate telepathically, Hiero attempts to uncover what has become of some colonies that his abbey has attempted to establish. Hiero's eventual allies include Gorm, a telepathic black bear, and Luchare, a princess from the distant kingdom of D’alwah. On his journey he faces many dangers, including mutated humans, mutant beasts, and the evil forces of The Brotherhood of the Unclean.
Several reviewers note that the novel reflects Cold War sensibilities, including fears of a nuclear holocaust wiping out civilization. The presence of a Christian religious order is also reminiscent of the novel A Canticle for Leibowitz.
Hiero's Journey was the first book in a planned trilogy, but only the sequel, The Unforsaken Hiero was ever published.