The ancient town of Si Thep is one of the most significant Dvaravati culture sites. It is located on rolling plains approximately 4 kilometers east of the Pa Sak River, in Si Thep District, Phetchabun Province. The area is approximately 60 - 80 meters above sea level. Si Thep is located next to western margin of the Khorat Plateau, in the central highlands, a significant hub for exchange trade and networks between the central and northeastern regions during the late prehistoric period and Khmer culture period in the 13th century CE.
Archaeological and historical evidence indicates the areas where ancient town of Si Thep and its vicinity are located have continuously been used since the late prehistoric period, approximately 1,700 – 1,500 years ago. That time saw a dramatic increase in population number and density, coupled with intensive salt and iron production, leading to widespread occupation across the Lopburi-Pa Sak river valley. A survey of area in the radius of 15 kilometers from the ancient town of Si Thep has identified at least six various prehistoric sites, including habitation sites, stone ornament workshop sites, and ritual or burial sites.
The prehistoric communities in the area of Si Thep were agriculturally-based, and consisted of several small villages and each village had a leader. People excellently knew how to live and manage themselves to co-exist with natural environments. They practice rice cultivation and animal domestication, as well as hunting and collecting available natural resource. In addition, weaving, pottery-making, and metal smelting were also performed in the community. People might have believed in the afterlife or the next world as they buried the dead with a variety of grave goods. A radiocarbon AMS dating of a human canine from the site yielded an age of 1,730 ± 30 years ago.
In addition, Indo-Pacific beads and accessories were discovered, including agate and carnelian beads, jade bracelets, and engraved ivory combs, providing evidence for inter-regional trade and exchange.
An important factor contributing to the settlement at Si Thep is the strategic location. The community is situated in an arena where two major cultures have interplayed: the “Lopburi-Pa Sak River Valley culture” in central region and the “Northeast Basin culture” in the Khorat Plateau in northeastern region. There are five natural channels and gates on the Phetchabun mountain range which served as a means of contacts and interactions between people of the two cultures. Furthermore, the location of the ancient Si Thep community is the convenient reach of people from coastal communities who were also actively engaged in the long-distance maritime trade and exchange network with people in the inland communities, including Si Thep. This is witnessed by the discoveries of glass and semi-precious stone beads, jade ornaments, and an Indian ivory comb. The inter-regional trade and contacts with India has essentially led to the rise of more complex settlements in later times. Si Thep is among the earliest communities in Thailand that made contacts with India, as evidenced by a stone inscription, No. K 978 Inscription, written in Sanskrit with Pallava scripts dated to the 6th century CE. As a result, Si Thep was developed into an early state in parallel with other early Southeast Asian states including Funan, Chenla, and Sri Ksetra.
Si Thep is a hinterland town affiliated with Dvaravati culture (ca. 6th-11th centuries CE), located on the trade route and served as a center for inter - regional contacts with communities and towns in the Upper Chao Phraya river valley in the west and those in the Khorat Plateau in the east. As a key middleman and supplyer, Si Thep controlled the flow of products needed by internal communities and distributed trade items to other communities that made frequent contacts with coastal communities.
As a major religious center, Si Thep played an important role in receiving and transferring various religious cultures including Dvaravati Buddhism from central region, Hinduism from ancient Khmer kingdom, and Mahayana Buddhism from northeast region.
With regard to artistic tradition, Si Thep produced a unique, important and outstanding art style reflecting a creative genius in art production.
Physically, Si Thep is characterized as a walled and moated town consisting two main parts, the inner town and the outer town, occupying a total area of measuring 4.7 square kilometers.
The Inner Town is relatively round in shape and covers an area of approximately 1.87 square kilometers. It encompasses a series of rolling plains, and there are 48 Buddhist and Hindu ancient monuments in this part of the town. The Buddhist monuments are associated with Dvaravati culture (7th-11th centuries CE), while the Hindu monuments show strong influence of ancient Khmer art style (11th-13th centuries CE). The large and significant monuments are Khao Khlang Nai, Prang Si Thep, and Prang Song Phi Nong. In addition, there are more than 70 ancient reservoirs of different size in this part.
The Outer Town is located to the east of the inner city, covering an area of approximately 2.83 square kilometers. It is a rectangular in shape with rounded corners, and there are 64 ancient monuments and structures, as well as numerous reservoirs, found in this part of the town.
Additional 50 ancient monuments have been identified found outside of the town, most of them are located in northern part of the town. The major monuments include Khao Khlang Nok, Prang Rue Si, and Khao Khlang Sa Kaeo monument complex, and Sa Kaeo pond. Approximately 15 kilometers to the west of Si Thep is the location of an enormous limestone mountain with a unique outlook called Khao Thamorat, also known as Khao Yai among the local villagers. This mountain has been used as an important travel landmark since prehistoric times. A number of prehistoric stone ornament workshops have been found at the foothill. Later in Dvaravati period, a limestone cave was modified to serve as Mahayana Buddhist sanctuary dating to the 9th century CE.
Si Thep was prosperous for more than 700 years before gradually losing its significance during the late 13th century CE due to the emergence of the new Lavo and Phimai cities in the northeast. After the breakdown of the Khmer Kingdom in the late 13th century CE, Sukhothai emerged as a new political hub in north of Chao Phraya River along with Phra Nakhon Si Ayutthaya on the Chao Phraya basin, causing a shift to the original inter-cities trade and exchange route and the gradual decline leading to the abandonment of Si Thep.
Si Thep was home to a late prehistoric period community that flourished in the Lopburi – Pa Sak river valley 1,700 - 1,500 years ago (circa 3th to 5th centuries CE). Once external cultures, particularly ancient Indian and Khmer cultures were introduced, Si Thep grew into an urban Dvaravati center between the 6th and 11th century CE. After that, it transitioned into an even more complex town quite strong influence of ancient Khmer culture in the 11th and 13th century CE. After a period of approximately 700 years of continuous occupation and regional significance, Si Thep began to decline during the late 13th century and was completely abandoned soon after that.
The chronological development of Si Thep indicates that the town play an important role as a hinterland and a center of trade, exchange, and culture through a long period of time. It was also engaged in inter-regional cultural and economic exchange networks, serving as hub on an ancient trade route linking people from central plains in the central region and the Khorat plateau in northeastern Thailand, as well as areas in the east and west of Southeast Asia. The strategic location of Si Thep is an important factor enhancing economic role of the town as a center of trade and culture in Thailand, Southeast Asia. The outstanding characters of Si Thep are numerous, including the followings.
Archaeological excavations at Si Thep revealed evidence of human settlement as a farming village dating to the late prehistoric period around 1,700 - 1,500 years ago. The town is located in the well-chosen area consisting of alluvial plains flanked by Pa Sak river and the Phetchabun range on the western margin of the Khorat Plateau. In the area, there are rivers that served as waterways and perennial sources of water, as well as abundant natural resources including minerals and forest products for subsistence and exchange. There is also a large mountain located approximately 15 kilometers west of the town. This mountain served as landmark to facilitate transportation between communities. The town is located between the Khorat Plateau in the Northeast and the region just east of plains in the Central Plains region which could be linked to a maritime trade route. A combination of strategic advantageous location, abundant natural resources, and unique landscape has led and supported Si Thep to play a significant role the prehistoric exchange and trade networks, which led to cultural, technological, and political changes that culminated in the emergence of Dvaravati culture between the 6th and 11th century CE.
Si Thep was a large, complex and important city during the Dvaravati Period. The town plan was sophisticatedly designed to facilitate the occupation. Moats were constructed to bring water to numerous reservoirs in the town for consumption and religious use, and earthen walls were built to protect the town to facilitate the flow of water. The city plan was divided into zones of different activities and purposes. For example, the inner city was both a residential quarter for high status people and also for public religious activities and ceremonies. This is attested by major religious monuments, including Khao Khlang Nai, Prang Si Thep, and Prang Song Phi Nong. It is clearly noticeable that the monuments in the Outer Town are smaller and less impressive than those in the Inner Town. It is also possible that the outer city was designed as a habitation area for commoners and agricultural purposes.
The fact that numerous large monuments were part of the Inner Town, it is therefore believed that such monuments, particularly Khao Khlang Nok (1,200 BP) which is the largest monument of the town, might have served specific functions, probably pilgrimage and sacred religious activities. In addition, the location and position of Khao Khlang Nok and the orientation of Prang Si Thep and Prang Song Phi Nong is linked to Khao Thamorat, a sacred and important Buddhist cave filled with Buddha images, bas-relief of Buddha, the Wheel of the Law (a Buddhist symbol),and Bodhisattva image (8th – 9th centuries CE). On top of the mountain also stands a Dvaravati Period brick monument, symbolizing the significance of a Buddhist and Hindu cosmology on interrelationship between mountain and important religious monuments.
In regard to culture and religion, the ancient town of Si Thep played an important role in receiving and transmitting religious beliefs from two great cultures: the Dvaravati Theravada Buddhism from the Upper Chao Phraya Basin and Lopburi River Valley (6th – 11th centuries CE), and Hinduism and Mahayana Buddhism from the Northeast and ancient Khmer kingdom (7th – 13th centuries CE). This is evidenced by large Buddhist and Hindu monuments including Khao Khlang Nai, Prang Si Thep, and Prang Song Phi Nong.
Epigraphic evidence including stone inscriptions in Pali language in Pallava script strongly suggests a strong belief in Buddhism, as those inscriptions often mention Buddhist sermons as appears in Tripitaka such as the verse of ye dharma, the law of paticca samuppada (dependent origination), as well as the Dharmacakkappavatana Sutta (the Buddhist first sermon). In addition, many votive tablets have inscriptions written in Sanskrit language in Pallava script narrating about practices to attain the state of out-of-passion. A votive tablet from Ban Nong Sruang in Si Thep District of Phetchabun Province bears an inscription mentioning merit bestowing. Another important piece of evidence is an inscription in Sanskrit language in Pallava script on the front of a votive tablet translated as saying “World….Succession”. The back of the same votive tablet was inscribed with two Chinese characters, one character is a generic term mimicking the Pali word “Bhikkhu” which means “monk”, while the other character represents the name “Wenxian”. This suggests the widespread of Pali and indicates that Si Thep was an important international town in the 7th century CE. The discovery of seven statues of Surya, the biggest number ever discovered in Thailand, led to a hypothesis that Saurapathas sect was practiced in Si Thep. Moreover, there are many Theravada and Mahayana Buddhist structures such as stupas, pagodas, temples and buildings in Si Thep. Along with Buddhist monuments, there are also Hindu monuments in the form of god houses or shrines of various sizes built of brick and laterite located across the town, indicating that Si Thep was evidently a prominent center of diverse cultures and religions.
Many lines of evidence of artworks at Si Thep skilled suggests that this ancient town was home and hub of Theravada Buddhist culture from central Thailand and ancient Khmer Hindu culture together with Mahayana Buddhist culture from the Northeast. The three cultures were syncretized to form a unique style of art and then transmitted to other communities. The creation of art at Si Thep was inspired by religious art which is unique and different from contemporaneous arts. The creative genius on art by people at Si Thep reflects their knowledge, wisdom, and skills. This special and unique style of art has been called by Professor Jean Boisselier, a prominent scholar, “Si Thep School of Art”. Examples of “Si Thep School of Art” are iconic sculptures, which have been found at Si Thep in relatively large quantity, including statues of Vishnu, Surya, and Krishna. These statues were elaborately and realistically made. An exemplary sculptural art that represents such high level of craftsmanship is the bronze statue of standing Vishnu with slender body, wearing a tall conical cap (kirita-makuta), and bending at the waist and hip posture. This exotic form of Hindu sculptures is rare. A statue of standing Surya in similar posture and headdress adorned with floral motifs and wearing cloth in Scythian style was also discovered at Si Thep. This unique sculptural style of art is a rare example of artwork found exclusively at Si Thep.
Professor Jean Boisselier asserted that Si Thep School of Art is completely different from ancient Khmer sculptural art, in carving method and iconographic characteristics. It is believed that the Si Thep School of Art might have been developed in the 7th century CE and ended around the 9th century CE. It was inspired and influenced by a combination of Dvaravati art, Srivijaya art, and Khmer art. The stone sculptures executed by this school of art are regarded as the best and no other schools in Southeast Asia could compete with.
As for architecture, Si Thep artisans created a unique architectural style with detailed architectural elements. For instance, Khao Khlang Nai, a major Buddhist monument in the Inner Town, was adorned at the base with stucco dwarfs that are highly distinctive from those at other contemporaneous Dvaravati culture archaeological sites. These sculptures do not only exist in human form but also exist in animal form, such as monkeys, lions, elephants, and cows in the position of lifting or leaning. They exhibit a variety of different facial expressions and some are depicted in a flying pose.
Khao Khlang Nok, the brick stupa built on the world’s largest laterite base to date, is one of the biggest Dvaravati architectures (7th – 8th centuries CE) and is the most complicated monument in terms of form and plan, which followed in accordance with Cosmic Mandala believes. The details of the base decoration at Khao Khlang Nok represent artistic developments, inspired by panjara (a kind of wall ornaments depicted in niche shape) found in Indian artistic style since the 12th century CE. This art form was blended with the “flying pavilion” or the reproduction of Pre - Angkorian Khmer art style (circa late 6th - early 8th centuries CE) and the Central Java art. This resulted in unique characteristics, namely open corners of the castle base, decorated walls of the shrine, front stairs, arched entrance ways, and curved, sloped roof layers supporting the upper building with the shrines creating another layer. Khao Khlang Nok truly represents glory and considerable significance of Si Thep as a center of Mahayana Buddhism in the hinterland of Thailand.
Prang Si Thep, a brick monument dedicated to the Saivism in Hinduism, is apparently inspired by a Khmer architectural form commonly found in the Northeast, but it was recreated or adapted into a unique style of architecture of Si Thep. This Si Thep’s unique architectural style was presented at the pagoda of Phra Phai Luang Temple in Sukhothai Province and the tower-shaped stupa at Wat Mahathat in Lopburi Province.
The stone lintel depicting figure of Uma Maheswara at Prang Song Phi Nong is a locally modified version of the Khmer Baphuon art (12th century CE). Si Thep local artisans added unique characteristics by carving large adorned Naga, a generally image from Angkor Wat-style Khmer art, right next to both sides of Kala, whereas Kala’s hands touching to Naga instead of holding flower garlands in the way that was famous during the ancient Khmer period. The face of Shiva and Uma has some characteristics of the nativity. In addition, the number of details of the leaves under the flower garlands on the lintels of Si Thep is also unique, inspiring to the artistic style of Lopburi, as appears on the lintel of the main stupa of Phra Si Rattana Mahathat Temple (circa late 13th century CE).
In this regard, it can be said that the relatively well-preserved physical and cultural characteristics of Si Thep, as well as its monumental architecture and material remains, are clearly an eyewitness of wisdom of humans who wisely selected a location for settlement and designed the town plan and infrastructures to facilitate trade, exchange, cultural interaction, leading to the fruitful social and cultural developments over a long period of time. In addition, the town has gone through transformation and integration of local subsistence pattern in order to create an art that embraced religious believes into unique forms of their own, becoming one of the significant ancient cities in the early historic period of Thailand and Southeast Asia. In addition, artistic creations and believes were also transferred to the creation of artworks in later times.
Criterion (ii): Si Thep is a major and important town on the ancient trade route and networks in Southeast Asia, and it represents local inhabitants’ wisdom in choosing advantageous location suitable for connecting and diffusing culture and trade goods intra- and inter-regionally since prehistoric time, Dvaravati period, and ancient Khmer culture period.
The ancient town of Si Thep is the most important and the largest hinterland settlement in Dvaravati culture. It was developed from a prehistoric farming village in the Pa Sak valley approximately 2,500 - 1,500 years ago. This community was talented in selecting a location that linked the plains in the east-central region and the highlands in northeastern region, allowing the effective control and connection of the exchange of goods and culture. It became an important hub of exchange where goods from multi-directions were imported, being coastal communities, highland communities in the Northeast Plateau, as well as those from the central Chao Phraya basin in the west. Furthermore, Si Thep also served as a leading center of religious network by incorporating Dvaravati culture Theravada Buddhism from the Upper Chao Phraya Basin, and Mahayana Buddhism and Hinduism from the Khorat Plateau in the northeast.
Criterion (iii): Si Thep is an outstanding cultural headquarter in the hinterland of Thailand, showcasing genius and wisdom in the concretization and creation of religious art into its own art school.
Considering artworks created by local art masters and artisans of Si Thep, it is clearly discernable that most of artworks of Si Thep are related to religions being Buddhism and Hinduism. Though the artworks of Si Thep have been inspired by art styles from several places and schools, including Indian art, Theravada Buddhist art from Upper Chao Phraya Basin and the Lopburi River Basin, and Mahayana Buddhist art and Hindu art from northeastern region and ancient Khmer kingdom, but those art styles were uniquely and wisely adopted, modified and developed with high level of craftsmanship leading to the rise of “Si Thep School of Art”. This art school further inspired the production of sculpture and architecture throughout the Dvaravati culture (6th – 11th centuries CE) and the ancient Khmer culture (11th – 13th centuries CE).
In addition to archaeological objects, inscriptions, sacred sculptures based on religious belief, and all authentic objects that were discovered have been conserved and reserved in the National Museum. The evidence from parts of building that existed in Si Thep still remain and can represent all the forms and influences that took place throughout time, from archaeological excavation units dating to prehistoric period to the parts of the building in several eras since the very beginning era of Indian cultural transfer, the development of a unique style in the Dvaravati period, to the era influenced by Pre - Angkorian, Khmer culture period. After that, the center of the trade route was moved to another city, and local people gradually migrated to the new hub. Si Thep was then transformed into a deserted city in the late 13th century CE. Since then nature has played an important role in preserving the authenticity through the Sukhothai, Ayutthaya, and Bangkok periods, to the period of time when Fine Arts Department as a governmental entity responsible for the archaeological sites protection and conservation has taken care of Si Thep. As a result, none of the archaeological evidence of Si Thep was disturbed and everything still remains unchanged, particularly the full line of city walls, which are the most important evidence of this ancient city due to their size and style that exhibit their significance.
The Fine Arts Department of Thailand has announced the registration of archaeological complex in Si Thep and the surrounding area, namely Khao Khlang Nok and Prang Rue Si, announced in The Royal Gazette in March of 1963 (Volume 80, page 29). Si Thep has been established as a historical park since 1984. Although at that time there were some modern people who tried to settle down in the area, the site of the ancient city was not disturbed and nothing was built overlapping archaeological structures. Since this archaeological site was a significant as sacred places and created deeply spiritual values among the local people, it was preserved very well even before the Fine Arts Department took charge.
Since the area is managed in the form of a historical park, apart from using legal measures to help protect and conserve the archaeological site, there has also been some academic studies conducted in the areas of archaeology, history, and other disciplines related to archaeological site excavation and architectural styles. In addition, the conservation and renovation performed to reinforce the archaeological sites were conducted in accordance with international standards to preserve the authenticity of the original shape and form, materials, craftsmanship, and settings. Significant authentic sculptures, such as those found at Khao Khlang Nai have been conserved with roofing methodologies to cover all materials and craftsmanship. As for other parts, despite the introduction of new materials for restoration, the new materials still remained authentic and were used minimally only to reinforce the structure, based on the understanding on architectural structures received from archaeological evidence.
To maintain the authenticity of setting, the Master Plan for Conservation and Development of Si Thep, was created, leading to continuous implementation into the present. Consequently, Si Thep has maintained its authenticity extremely well. The inner area of the ancient city has been managed and zoned based on each particular significant archaeological areas. Facilities and amenities are well provided. There is also control over the new construction to avoid disturbing the authenticity of the setting of archaeological sites, as well as to control the community area so visitors stay outside of the ancient city moat. In general, the setting around Si Thep is also an agricultural area. There is no large urban development or high building construction that affects the ambiance of Si Thep ancient city. Particularly, there is no disturbance to the view along the connecting axes between Khao Khlang Nok, the key religious site outside the city to the north, and Khao Thamorat, the sacred mountain in the west side of this ancient city.
In addition to the authenticity of the tangible elements of Si Thep, although at present Si Thep exhibits only traces from the usage in the past, the value of sacred places still remains important among locals. It is therefore considered that the spiritual authenticity and other intangible values have been well conserved, as evidence shown through the continuous organization of a huge worship ceremony on an annual basis.
Si Thep was continuously developed beginning in the late prehistoric period, through the eras influenced by Dvaravati culture and ancient Khmer culture, and ultimately was abandoned by the late 13th century. Another group of people moved into the area again in the Bangkok period. All elements of this ancient city not only enhance its significance in terms of academic and scenic landscape, but also create important values to people socially, economically, and spiritually on a continuous basis. As a result, this location still has strong influence in the lives and beliefs of modern local people.
The renovation and restoration of archaeological sites in Si Thep were conducted in accordance with academic theories to serve educational and tourism purpose. Under the Master Plan for Conservation and Development of Si Thep, the site has received excellent conservation and protection to maintain their value as sites of cultural heritage. In addition, the lack of disturbance from construction within the archaeological site area also helps confirm that nothing can diminish the importance of the archaeological site in the future.
My Son Sanctuary in Vietnam was declared a World Heritage Site in 1999 based on the Outstanding Universal Values, Criteria 2 and 3. This sanctuary is considered an example of one of Vietnam's most important features of cultural heritages that represents cultural transfer and the unique syncretism with Indian culture, comprising of Hindu arts and architectural features in areas under the rule of the powerful Cham Empire. The Cham Empire continuously influenced cultural transfer throughout Southeast Asia.
2. Pyu Ancient Cities, Myanmar
Pyu Ancient Cities is located in the Irrawaddy River Basin in Myanmar. This group of cities is comprised of archaeological evidence including brick city walls, moats, and clay embankments from three cities: Halin, Beikthano, and Sri Ksetra. These cities were significant in the Pyu State during the 4th – 9th centuries. Archaeological analysis found evidence of a fortresses, cremation rituals, brick Buddhist stupas, and a moat with clay embankment structures built for use in water management. Some moats and clay embankments are still usable nowadays. Halin, Beikthano, and Sri Ksetra are considered the pioneers of cultural world heritage in the Serial Property category in Southeast Asia, dating between the 4th and 9th centuries. The group of Pyu ancient cities in Myanmar was declared a World Heritage Site in 2014 based on the Outstanding Universal Values, Criteria 2, 3, and 4.
Pyu ancient cities are a cultural resource that shows the Indian cultural transfer that occurred during the 6th century. Pyu Ancient Cities are considered the first cities in Southeast Asia where Buddhism was established. There are several Buddhism-related buildings and brick pagodas. The architecture styles were adapted from external culture into the unique Pyu architectural styles. The Buddhist culture in Pyu Cities was also transferred to and led to changes in other parts of Southeast Asia since the early common ear through Buddhism doctrines and practices. The Pyu ancient complex is considered to be the first area in history where Buddhism was originally established in Southeast Asia. The construction of Buddhist venues for ceremony organization led to seasonal agricultural area management and water management for utilization and consumption, and the production of potteries, steel, gold and silver items for trading purposes, and the construction of brick Buddhist venues under royal sponsorship. Additionally, new mortuary practices were initiated, crematoria were constructed, and people began to keep cremated human remains in urns. During this time, commercial network between Pyu ancient cities and other locations in Southeast Asia, China, and India, were established, contributing to the use of Pali in Southeast Asia in the Buddhist scriptures.
Cultural waves from outsides forced Pyu to develop management strategies in several areas, such as agriculture, brick production, and metal production, for utilization within cities. This resulted in the advancement in terms of city planning and building constructions, such as the construction of temples with surrounding walls, moats and canals around Buddhist venues, tall pagodas, and the location of the palace in the area close to or right at the center of the city. These all were derived from the beliefs on centralized governance and the Cosmic Mandala.
3. Sombor Prei Kuk Archaeological Site Representing the Cultural Landscape of Ancient Ishanapura
Sombor Prei Kuk is an Ishanapura cultural landscape in Cambodia. It was designated as a Cultural World Heritage Site in 2017 at the 41st Session of the World Heritage Committee based on the Outstanding Universal Values, Criteria 2, 3, and 5. This cultural heritage site has distinctive characteristics in terms of architecture and city planning, both of which were influenced by Indian culture. In addition, there are also some unique aesthetic decorations, such as the sculpture of a castle, coin-shaped picture frames on the brick walls of religious buildings, and lintels used to furnish religious venues in the artistic style known as Sombor Prei Kuk Art. This cultural heritage site also has a landscape design with water management system allowing water flowing cycle and water collection for all year utilization.
The ancient Ishanapura civilization came from Indian culture and played an important role in the Khmer Empire, influencing the social, religious, and artistic structure and contributing to unique traditions, values, and arts. This is particularly true of the Chenla Kingdom, the linking hub between Hinduism and Buddhism, which impacted many societies throughout Southeast Asia. Sombor Prei Kuk is also one of the largest monastic sites in Southeast Asia with traces of evidence from brick and stone constructions, similar religious beliefs, and languages, representing a civilization that continues to exist into the present.
Languages and inscriptions found at Sombor Prei Kuk are evidence of the initial use of Khmer and later addition of Sanskrit language. This area was a centralized governance center and the foundation of the Khmer royalism that existed until the beginning of the 20thcentury. In addition, carvings on the lintels of Sombor Prei Kuk Sanctuary depict a pattern of musical instruction and musical instruments, which is important evidence of ancient musical education in Cambodia. In the past, Ishanapura was the center of the cosmos in terms of governance, language, and religion.
Although some criteria of these cultural world heritages are similar to the ancient town of Si Thep but the characters of this ancient town produced a unique, important and outstanding. With the origin of Si Thep is ancient community settlements in the late prehistoric period, approximately 1,700 years ago. Once external cultures, particularly ancient India and Khmer cultures were introduced, Si Thep grew into an urban Dvaravati center during 6th - 11th centuries after that, it transitioned into an even more complex town quite strong influence of ancient Khmer culture in the 11th – 13th centuries.
The city planning of Si Thep involved the construction of moats surrounded by city walls that were divided into two parts. Both parts were built concomitantly; to the east of the city, there is a significant mountain, Khao Thamorat, and clay embankments were constructed to control water flow into the city. This was a concept of city planning to meet the needs of people living during the 7th – 11th centuries at the beginning of the Dvaravati Period. In that time, the cave in Khao Thamorat was reconstructed into a sanctuary. It is believed that the origin of belief that led to the construction of the sanctuary in a cave was from cultural transfer since caves were believed to be a place for religious ceremonies in Indian belief systems. For the Indian context, there is a cave sanctuary called a Chediya Stan (Place of Worship). It is a human-made cave dating to the ancient Indian period (200 BC – 1st century) and Gupta Empire.
The large number of brick and mortar sanctuaries inside and outside this ancient city. Especially Khao Khlang Nai, stucco sculptures of dwarfs decorating this monument have distinctive characteristics different from those of other contemporary Dvaravati culture archaeological sites. These sculptures do not only exist in human form but also exist in animal form, such as monkeys, lions, elephants, and cows in the position of lifting or leaning. They exhibit a variety of different facial expressions and some are depicted in a flying pose. These characteristics were never found anywhere else and are assumed to have been developed and added into artworks by local Si Thep artisans, helping invent gnome sculptures not seen anywhere else.
The monument of Khao Khlang Nok, the world’s largest laterite base to date, is one of the biggest pagoda in Dvaravati architecture and is the most complicated architectural feats in terms of structural planning and construction process, which followed in accordance with Cosmic Mandala beliefs. The details of the base decoration at Khao Khlang Nok represent artistic developments during the 8th – 9th centuries, inspired by the systematic of panjara (a kind of wall ornaments depicted in niche shaped) system in Indian artistic style in use since the 12th century, blending forms of “flying pavilion” or the reproduction of Pre-Angkorian-style, Khmer Art (circa late 6th - early 8th centuries). This resulted in unique characteristics, namely open corners of the castle base, decorated walls of the shrine, front stairs, arched entrance ways, and curved, sloped roof layers supporting the upper building with the shrines creating another layer. These represent beliefs and architectural style influenced by India, as well as the prosperity of Si Thep as the significant hub of Mahayana Buddhism for the inner region of Thailand.
The creation of art at Si Thep was inspired by religious art which unique and different from contemporaneous arts. The creative genious on art by people at Si Thep effects their knowledge, wisdom and skills.This special and unique style of art has been called by art historian ‘Si Thep School of Art’. Some sacred sculptures were also found in Si Thep, such as statues of Narai or Vishnu wearing a cylinder hat, Krishna lifting up Kavawatana Mountain, and Surya (the Sun God). The most traces of Surya worship in Thailand were found at Si Thep, where 7 statues of Surya were found. This discovery led to the assumption of the existence of the Saurapathas sect, who believed that God Surya (the sun deity) is the highest spirit who built the cosmos and is the spirit of both animate and inanimate objects. God Surya was also believed to be a secondary god in the Vaishnavism which might be transferred from North India and the Bay of Bengal.
The sacred sculptures of Si Thep School of Art is completely different from Khmer sculptural art in carving method and iconographic characteristics. It is believed that the Si Thep School of Art might have been developed in the 7th century and ended around the 9th century. It was inspired and influenced by a combination of Dvaravati art, Sri Vijaya art, and Khmer art. The stone sculptures executed by the school of art are regarded as the best and no other schools in Southeast Asia could compete with.