The monumental oak King of Kings (Le roi des rois, 1938) was originally intended to stand in Brancusi's Temple of Meditation, a private sanctuary commissioned in 1933 by the Maharaja Yeshwant Rao Holkar of Indore. Although never realized, the temple—conceived as a windowless chamber (save for a ceiling aperture) with interior reflecting pool, frescoes of birds, and an underground entrance—would have embodied the concerns most essential to Brancusi's art: the idealization of aesthetic form; the integration of architecture, sculpture, and furniture; and the poetic evocation of spiritual thought.
Wood elicited from Brancusi a tendency toward Expressionism, resulting in unique carved objects. While his sculptures executed in stone or metal represent archetypal forms, such as birds in flight and sleeping figures, individual works in wood suggest specific characters or spiritual entities. For example, King of Kings may be interpreted as Brancusi's attempt to translate the power of Eastern religion into sculptural form. The work's original title was Spirit of Buddha (L'esprit du Bouddha), and Brancusi is known to have been familiar with Buddhism through the writings of the Tibetan philosopher Milarepa.
Although the extent to which Brancusi's work was inspired by African sculpture and Romanian folk carvings has been widely debated among scholars, it is clear that he was acutely responsive to "primitivizing" influences early in his career. Paul Gauguin's technique of direct carving to emulate the raw quality of indigenous Tahitian art inspired Brancusi to experiment with more daring approaches to sculpture than his academic training had previously allowed. Gauguin's aesthetic most likely prompted Brancusi to study tribal art, evident in the serrated patterns typical of African carvings on the bottom portion of Adam and Eve (Adam et Eve, 1921) as well as on the sides of King of Kings. The overt sexual references in the former work may also have been inspired by so-called primitive fetishes.
Sculptural sources from Brancusi's native country are also abundant: prototypes for the sequential designs of King of Kings have been found in Romanian vernacular architecture such as wooden gate posts and chiseled ornamental pillars. The Sorceress (La sorcière, 1916–24), pictured with Watchdog (Chien de garde, 1916), has been interpreted as the flying witch described in Romanian peasant tales. Brancusi never clarified the visual sources for his designs, preferring instead to promote an air of mystery surrounding the origins of his vision.