Sacred king

In many historical societies, the position of kingship carries a sacral meaning, that is, it is identical with that of a high priest and judge. The concept of theocracy is related, although a sacred king need not necessarily rule through his religious authority; rather, the temporal position has a religious significance.
History.
Sir James George Frazer used the concept of the sacred king in his study "The Golden Bough" (1890–1915), the title of which refers to the myth of the Rex Nemorensis. Frazer gives numerous examples, cited below, and was an inspiration for the myth and ritual school. However, "the myth and ritual, or myth-ritualist, theory" is disputed; many scholars now believe that myth and ritual share common paradigms, but not that one developed from the other.
According to Frazer, the notion has prehistoric roots and occurs worldwide, on Java as in sub-Saharan Africa, with shaman-kings credited with rainmaking and assuring fertility and good fortune. The king might also be designated to suffer and atone for his people, meaning that the sacral king could be the pre-ordained victim in a human sacrifice, either killed at the end of his term in the position, or sacrificed in a time of crisis (e.g. the Blót of Domalde).
The Ashanti flogged a newly-selected king ("Ashantehene") before enthroning him.
From the Bronze Age in the Near East, the enthronement and anointment of a monarch is a central religious ritual, reflected in the titles "Messiah" or "Christ", which became separated from worldly kingship. Thus Sargon of Akkad described himself as "deputy of Ishtar", just as the modern Catholic Pope takes the role of the "Vicar of Christ".
Kings are styled as shepherds from earliest times, e.g., the term applied to Sumerian princes such as Lugalbanda in the 3rd millennium BCE. The image of the shepherd combines the themes of leadership and the responsibility to supply food and protection, as well as superiority.
As the mediator between the people and the divine, the sacral king was credited with special wisdom (e.g. Solomon or Gilgamesh) or vision (e.g. via oneiromancy).
Study.
Study of the concept was introduced by Sir James George Frazer in his influential book "The Golden Bough" (1890–1915); sacral kingship plays a role in Romanticism and Esotericism (e.g. Julius Evola) and some currents of Neopaganism (Theodism).
The school of Pan-Babylonianism derived much of the religion described in the Hebrew Bible from cults of sacral kingship in ancient Babylonia.
The so-called British and Scandinavian cult-historical schools maintained that the king personified a god and stood at the center of the national or tribal religion. The English "myth and ritual school" concentrated on anthropology and folklore, while the Scandinavian "Uppsala school" emphasized Semitological study.
Frazer's interpretation.
A sacred king, according to the systematic interpretation of mythology developed by Frazer in "The Golden Bough" (published 1890), was a king who represented a solar deity in a periodically re-enacted fertility rite. Frazer seized upon the notion of a substitute king and made him the keystone of his theory of a universal, pan-European, and indeed worldwide fertility myth, in which a consort for the Goddess was annually replaced. According to Frazer, the sacred king represented the spirit of vegetation, a divine John Barleycorn. He came into being in the spring, reigned during the summer, and ritually died at harvest time, only to be reborn at the winter solstice to wax and rule again. The spirit of vegetation was therefore a "dying and reviving god". Osiris, Dionysus, Attis and many other familiar figures from Greek mythology and classical antiquity were re-interpreted in this mold. The sacred king, the human embodiment of the dying and reviving vegetation god, was supposed to have originally been an individual chosen to rule for a time, but whose fate was to suffer as a sacrifice, to be offered back to the earth so that a new king could rule for a time in his stead.
Especially in Europe during Frazer's early twentieth century heyday, it launched a cottage industry of amateurs looking for "pagan survivals" in such things as traditional fairs, maypoles, and folk arts like morris dancing. It was widely influential in literature, being alluded to by D. H. Lawrence, James Joyce, Ezra Pound, and in T. S. Eliot's "The Waste Land", among other works.
Robert Graves used Frazer's work in "The Greek Myths" and made it one of the foundations of his own personal mythology in "The White Goddess", and in the fictional "Seven Days in New Crete" he depicted a future in which the institution of a sacrificial sacred king is revived. Margaret Murray, the principal theorist of witchcraft as a "pagan survival," used Frazer's work to propose the thesis that many kings of England who died as kings, most notably William Rufus, were secret pagans and witches, whose deaths were the re-enactment of the human sacrifice that stood at the centre of Frazer's myth. This idea used by fantasy writer Katherine Kurtz in her novel "Lammas Night".
Examples.
Monarchies carried sacral kingship into the Middle Ages, encouraging the idea of kings installed by the Grace of God. See:
In fiction.
Many of Rosemary Sutcliff's novels are recognized as being directly influenced by Frazer, depicting individuals accepting the burden of leadership and the ultimate responsibility of personal sacrifice, including "Sword at Sunset", "The Mark of the Horse Lord", and "Sun Horse, Moon Horse".
In addition to its appearance in her novel "Lammas Night" noted above, Katherine Kurtz also uses the idea of sacred kingship in her novel "The Quest for Saint Camber".
References.
General
"English school"
"Scandinavian school"