When the great King Anawrahta of Pagan united the whole of Burma into a single kingdom in the eleventh century and made Theravada Buddhism the national religion, there were already in existence a number of primitive religious cults, the most important and the most popular of which were the worship of ''Nat" spirits, astrology, and alchemy. In addition, there were also Mahayana Buddhism and Tantric (or magical) Buddhism, but debased and distorted, and bearing strange fruit from the fertile soil of native cults of magic and sorcery. All the different cults were given an artificial unity by the fact that they were all under the patronage of the Ari monks. These Ari monks had some acquaintance with the Buddhist scriptures, gloried in the name of the Buddha, and wore dark brown robes and conical hats. But they also presided over the Nat spirit festivals, at which hundreds of animals were sacrificed.

Astrology to the Burmese meant not only the methods of tracing the courses of the planets and their influence on mortals, but also the ritual by which the planets were appeased and made to withdraw their baneful influence. In other words, it involved a worship of the planets. As Burmese astrology had its origins in Hindu astrology, the worship of the planets also involved worship of at least some of the Hindu gods.

Alchemy also came to Burma from India, but Burmese alchemy became a religious cult. The Burmese alchemist did not merely seek the power to transmute base metals into gold, but had the noble aim of evolving an eternally youthful body, which would be an answer to the perpetual human lament that beauty and youth must pass.

The worship of Nats was purely native in origin, and developed out of that form of animism which still prevails among some of the hill peoples of the country. The term "Nat" originally meant a "lord," and involved an idea similar to feudal overlordship. A Nat was a spirit who had some dominion over a group of people or over a certain object or objects. The spirit who had dominion over a small withered tree was as much a Nat as the spirit who had dominion over a particular village or district. The suzerainty of a Nat was both territorial and personal. The Nat guardian of a village had power over all those who were born in the village or born of a village family, wherever they might be, and he also had power over all who came to his village, during the time they remained there. He would inflict no harm, nay, he would even give his protection, to those who recognized his suzerainty, and such recognition could be expressed by an offering of rice or fruit, or by a few words of supplication, or a gesture of homage.

At first the Nats that were worshiped were impersonal and local, as for example, the Nats of the banyan tree, the hill, and the lake which were just outside the village, and the guardian Nat of the village. Later on, thirty-six personal and national Nats came into being, who were distinct personages with their own life histories, and who were worshiped all over the country. They did not replace the local Nats, but diminished their importance.

The most important of the thirty-six were the Lord of the Great Mountain, and his sister Lady Golden-Face, whose abode was on Mount Popa, an extinct volcano in central Burma. They became, in the ninth century, the guardian gods of the city of Pagan and its kings. There was an annual Nat feast on Mount Popa itself, at which hundreds of animals were offered as sacrifice to the Lord of the Great Mountain and Lady Golden-Face. People came from afar to take part in the feast, to get drunk with ecstasy and toddy wine, and to dance with abandon, believing themselves to have become possessed by the Nats. There were spirit mediums in attendance at the Nat shrines, who provided the wild music and led the wilder dances. The Popa feast was held on a full moon day in December, and on other full moon days there were also feasts connected with other pre-Buddhist cults.

When Anawrahta made Theravada Buddhism the national religion of the country, opposition came naturally from the Aris, and because they exercised great influence over the people, the king had no choice but to resort to religious persecution. The Ari monks were unfrocked, and made to serve in the royal armies. All the images of the gods of the planets and the Hindu gods were seized and placed in a Vishnu temple, which was renamed "The Prison of the Gods." All the pre-Buddhist cults were suppressed. Spirit mediums left the shrines to become strolling musicians, dancers, and actors.

But the people found it difficult to discard at once old beliefs and old practices, and resorted to stratagem. The followers of the cult of alchemy modified their conception of an eternally youthful body to that of a body remaining youthful for thousands of years, in order to conform to the Buddhist doctrine that nothing is permanent, and justified their search for the elixir of youth by saying that they wanted to live until the coming of the next Buddha so that they could listen to his preaching. The followers of the cult of astrology threw a veneer of Buddhism over their ritual and ceremony, as for example in the case of the ceremony of the Nine Gods, where the gods of the nine planets gave way to Buddha and his eight disciples.

As for Nat worship, the people, in spite of the king's edicts, went on worshiping the Nats, and Anawrahta finally decided to bring them over into Buddhism. The figures of the thirty-six lords were taken from their shrines, and placed in the king's great pagoda, in an attitude of worship, and he declared that the number was now thirty-seven, because Sakra, the king of the gods and guardian of Buddhism, was at the head of the pantheon. The cult of Thirty-Six Lords therefore became the cult of the Thirty-Seven Lords, and Anawrahta replaced some of the earlier lords with the Nat spirits of some of his dead heroes.

All this was possible, because the Burmese concept of the Nat was a very comprehensive one and took in under its wing Hindu gods as well as Buddhist figures. As the Nats themselves were now shown to be worshipers of the Buddha, it was deemed proper for Buddhists to worship the Nats. The feasts of the full moon became festivals of the full moon on being given a coating of Buddhism, just as pre-Christian feasts of spring and midwinter in Europe became the great Christian festivals of Easter and Christmas.

With the passing of time, people came to forget the pre-Buddhist and primitive origins of their folk beliefs in alchemy, astrology, and Nats, and learned to accept them as part of their Buddhism, just as they thought that the pre-Buddhist belief in the transmigration of souls was a doctrine of Theravada Buddhism. Thus, at the present day, many (and in rural and primitive areas the majority) of Burmese still consult their astrologer and make their offerings to the Nats, without ceasing to be good Buddhists. At certain times of year dances are still held through which the dancers try to become possessed by the Nat spirits, and a few Burmese still even make alchemic experiments.

But such beliefs and practices cannot overwhelm Buddhism in any way, for they have been shorn of their primitive meaning and philosophy. The Burmese who resort to astrology, alchemy, or Nat worship, do so for safety and success in their mundane life, and the same Burmese will observe the Buddhist religious days and perform deeds of merit in preparation for the countless existences that they must undergo in the whirlpool of rebirth.