Why Hinduism Rose and Fell in Southeast Asia
In December 2025, during a conflict along the disputed Thai-Cambodian border, the Thai military allegedly demolished a statue of the Hindu god Vishnu, triggering criticism from the Indian government’s Ministry of External Affairs (MEA). Many were surprised to learn that the state religion of the Khmer — as the majority ethnic group of Cambodia is known — was once Hinduism. India and Southeast Asia share deep ties to Hinduism. Why did Hinduism spread from India to Southeast Asia, and why did it subsequently decline? The answers are complex, and require a deep look at both Hinduism’s and Buddhism’s nature and evolution.
Hinduism and Buddhism both originate in ancient India, amongst a people who called themselves aryas. Whilst today, both are conceptualized as doctrinally well-defined and separate religions, in ancient times, the situation was more complex. What we today know as Hinduism grew out of the tradition of the Vedas — ancient Sanskrit scriptures — as expounded by the increasingly hereditary Brahmin (priestly) class, but also included many kshatriyas (warriors and kings). Buddhism, on the other hand, was an alternative movement that did not hold the Vedas to be authoritative and often put a different spin on the concepts of rebirth, the soul, karma, and dharma. The Buddha founded the sangha, a monastic order that, though theoretically open to all, was mostly dominated by Brahmin and kshatriya monks. Indian, Chinese, and Persian records all refer to Hindus and Buddhists — Brahmins and Śramaṇas in the language of that time — as the twin religious orders of ancient India.
The Vedic religion — Hinduism — and Buddhism, along with a number of smaller traditions, such as Jainism, hovered above a society with popular religious beliefs. The majority of people in ancient India — and ancient Southeast Asia, for that matter — followed the cults of famous deities and heroes, along with folk and local beliefs. In ancient India, Hinduism and Buddhism grew or shrunk in a region based on economic patterns, how well they accommodated local beliefs, and the needs of kings.
Each of the two religions has its advantages and disadvantages for a polity, as well as particular characteristics that would explain their later trajectories in Southeast Asia.
Buddhism, being a religion that anyone in theory can participate in, grew with trade and the urbanization of India during the Mauryan era (321–185 BCE) and afterward, as trade with the Roman world boomed. According to historian William Dalrymple, writing in “The Golden Road,” Buddhism was patronized by merchants, many of whom traveled to Southeast Asia in search of spices, thus introducing Indian culture there. The ability of Buddhism to decouple from its Indian origins is why Buddhism has generally spread farther than Hinduism, becoming the religion of groups living far from India, in Siberia, as well as manifesting as another Chinese religion by the time it reached Japan.
Hinduism — like Judaism — has some characteristics of an ethnic religion, with beliefs and rituals that are particular to a specific culture. Both Hinduism and Judaism are also not so narrowly construed so as to preclude conversion and spread. Throughout history, entire nations have become Hindu or Jewish, though not at the frequency of more universal religions, such as Christianity, Islam, and Buddhism.
Hinduism — unlike Buddhism — does not need to depend on a state or a body of lay followers to support it, as Brahmins are a self-perpetuating group. According to author and journalist Tony Joseph, an expert on ancient India, Brahmanical culture is also less dependent on urban spaces, which are often at the vicissitudes of trade, and is more deeply rooted in agriculture. Since most ancient states were rooted in agriculture and most of their populations lived in rural areas, they needed traditions that fit that reality.
Royalty also tends to favor Hinduism and Brahmins as the Vedic tradition has many rituals for the consecration of kings and ideas on the maintenance of the social order, as can be found in the classical Sanskrit epics, the Ramayana and Mahabharata. Buddhism has less to say about how society should be organized or how kings should be legitimized. In countries such as China and Japan, Confucianism and Shinto have filled this role — in fact, Shinto sought to borrow Hindu elements so as to construct an indigenous tradition along the lines of Hinduism. Even in Thailand and Cambodia, where Theravada Buddhism prevails today, Brahmins and Hindu rituals are essential for providing the framework for royal ideology.
Furthermore, the metaphysics of the Vedic tradition aligned more closely with popular religion in India, and common beliefs: most people would rather believe in the eternity of their atma (soul), as Hinduism has it, rather than the Buddhist view that there is no soul and that nirvana will result in its dissolution.
By the turn of the Common Era, the tradition of the Brahmins had integrated local beliefs, resulting in an ever-more robust, expanded Hinduism as popular texts known as the Puranas spread this synthesis, pilgrimages grew, and new temples were built. Rural India became increasingly populated with the shrines and establishments of Hinduism, and agricultural society was increasingly organized by Hindu sociopolitical theory, varnashrama dharma, or the gradation of society into hierarchical classes. Known as caste, this ideology, like Hindu deities and Hindu metaphysics, has evolved and reinvented itself many times throughout history, serving different roles in different places and times.
Hinduism is therefore particularly resilient in the Indian subcontinent because it has a large, organic base of both its adherents and leadership — after all, there are a lot more Brahmins in India than elsewhere. Buddhism, on the other hand, often withers away without state or donor support.
In the early centuries of the Common Era, religions such as Hinduism and Buddhism gained steam in Southeast Asia because they provided elites there with a fully-fleshed metaphysical package along with literacy, both useful for increasingly complex societies and aspiring kings. Christianity later fulfilled a similar role in northern Europe. On the other hand, Hinduism and Buddhism could not offer such a novel skills package further west, in Persia and Rome, where they did not make much headway, or in China, where Buddhism spread widely, but was sociopolitically subordinate to Confucianism.
Buddhism and Hinduism may have arrived in Southeast Asia together through trade, introducing Indian literacy and metaphysics. Buddhism had the edge at first, but Hinduism, specifically in its Shaivite and Vaishnavite — traditions that focus on the worship of Shiva and Vishnu, respectively, as the supreme deity — manifestations played a major role in state formation, especially in the nascent Khmer and Javanese polities, both of which depended heavily on agriculture. Contrast this with the long persistence of Mahayana Buddhism in the thalassocratic Srivijaya, based in Sumatra.
As Joseph notes, the influence of Buddhism across India and Southeast Asia began to wane as trade with the Roman Empire declined during that empire’s third century crisis. As agriculture — not trade — became the basis of state power, and as kings sought greater legitimacy, Hinduism became an increasingly attractive option. In both the Deccan peninsula of India and in Southeast Asia, kings invited Brahmins — who previously dwelt in their North Indian homeland — to settle and develop institutions and fallow land. However, for many centuries, numerous strands of Buddhism — particularly Mahayana Buddhism, which also prevails in East Asia — and Hinduism coexisted alongside local beliefs.
It is interesting to note that of the three ideologies available to aspiring Southeast Asian monarchs — Hinduism, Buddhism, and Confucianism — most went with the first: “the Hindu religion and its trappings offered the benefits of a royal ideology tailor-made for nascent Southeast Asian kings, with no political strings attached.” The first imperial Khmer monarch, Jayavarman II, was consecrated as chakravartin (universal monarch) in 802 CE by a Brahmin. For most of the Khmer Empire’s history, Hinduism remained the state’s dominant religion, and many famous temples were built at places like Angkor (Yashodharapura). Hinduism was used to organize society and promote the royal cult, the idea of the king as divine (devaraja). Similar forces were at work in other Hindu Southeast Asian kingdoms, such as Majapahit on Java and Champa in southern Vietnam.
Despite these successes, why did Hinduism disappear in Southeast Asia whilst persisting in India?
One hint of what may have happened is that Southeast Asia became much more important as a region, globally, in the 15th and 16th centuries as global trading patterns shifted in a seaborne direction. Islam spread in the Malay Archipelago through trade, particularly in mercantile city-states, whose rulers converted, perhaps due to extended interaction with Muslim merchants who stayed there for months awaiting favorable monsoon winds in order to sail back west to Arabia or India. Islam eventually spread throughout Java, and the rest of the archipelago, as most places in Indonesia are close enough to the sea to receive traders from afar. Hinduism only survived on the island of Bali.
Whilst in India, Buddhism was absorbed into Hinduism, mainland Southeast Asia followed a different trajectory. There, Hinduism and Mahayana Buddhism both began to decline in the eleventh and twelfth centuries, as new groups, like the Tai and Bamar, began to move into the area from the north. The states established by these groups increasingly patronized Theravada Buddhism, a hitherto minor school from Sri Lanka that had previously only been prevalent there and among the Mon states of Myanmar. Theravada Buddhism — relative to Mahayana and Tibetan Buddhism — tends to cleave more closely to the original canon and teachings of the Buddha, and as such, is more well-differentiated from Hinduism, and more resistant to absorption.
After the twelfth century, Theravada spread throughout mainland Southeast Asia, largely through missionary activity from Sri Lanka. The transition from Hinduism to Theravada Buddhism seems to be sudden and rapid. In the Khmer Empire, the first inscription in Pali — the liturgical language of Theravada — was in 1307 CE, while the last inscription in Sanskrit, a language associated with Hinduism, was in 1327 CE. Interestingly, it seems that the success of Theravada Buddhism in Southeast Asia was largely due to the same factors that made Hinduism successful in India — it “completely penetrated the land,” especially rural society, and became the default religion of the masses, while also incorporating folk animism and maintaining the role of Brahmins for royal rituals. The different fate of Hinduism in India itself can be chalked up to there being a larger critical mass of Hindus there and the deep connection there — both ethnic and philosophical — between elite and folk beliefs. Today — outside of Vietnam, which inherited the Chinese Confucian and Mahayana Buddhist traditions — most of mainland Southeast Asia is Theravada Buddhist, except for a few modern Indian immigrants, the royal Brahmins of the palace courts, and a small number of Chams in Vietnam.
Despite the triumph of Theravada in Southeast Asia, Hinduism has generally done better than Buddhism — which has sharply declined in the last century — in the modern world: this will be the subject of a future article. Both Hinduism and Buddhism have a long history in Southeast Asia, as well as differing fortunes. Their influence rose or fell based on trade patterns, socioeconomic trends, how well they incorporated local religions, and the needs of kings.
