"Devarāja" is the cult of the "god-king", or deified king in Southeast Asia.
The devarāja cult grew out of both Hinduism and indigenous traditions. It taught that the king was a divine universal ruler, a manifestation of the Hindu god, often attributed to Shiva or Vishnu. The concept viewed the monarch to possess transcendental quality, the king as the living god on earth. The concept is closely related to Indian concept of Chakravartin (universal monarch). In politics, it is viewed as the divine justification of a king's rule. The concept was institutionalized and gained its elaborate manifestations in ancient Java and Cambodia, where monuments such as Prambanan and Angkor Wat were erected to celebrate the king's divine rule on earth.
In Sanskrit the term deva-raja could have different meanings such as "god-king" or "king of the gods". In Hindu pantheon the title of king of gods is often attributed to Shiva, sometimes Vishnu, or previously Indra. Thus the mortal kingdom on earth mirrored the celestial kingdom of gods, the concept regarded the king as the living god on earth. It is also from influences in Hinduism and indigenous traditions.
Example of devaraja cult — such as demonstrated by Jayavarman II — associate the king with the Hindu god Shiva, whose divine essence was represented by the linga (or lingam), a phallic idol housed in a mountain temple. The king was deified in an elaborate and mystical ceremony, requiring a high priest, in which the divine essence of kingship was conferred on the ruler through the agency of the linga. The safeguarding of the linga became bound up with the security of the kingdom, and the great temple architecture of the Khmer period attests to the importance attached to the belief.