Orissa is proud of possessing a number of Buddhist centers where developed the Buddhist art and architecture. Important among these places are Ratnagiri, Udayagiri and Lalitagiri – popularly called the Diamond Triangle of Orissan – and Baneswaranasi of Cuttack district; Kuruma in Puri district, Dhauli, Banpur and Aragada of Khurda district, Boud in Boud district, Paragalpur and Syamasundrapur of Phulbani district; Solampur, Khadipada and Ayodha of Balasore district and Ganiapalli in Bargarh district.

We do not find any Hinayana art in Orissa. But a wealth of sculptures pertaining to Mahayana and Vajirayana School of art along with stupa, vihara and chaitya remnants constitute the Buddhist vestiges of Orissa. At Ratnagiri we come across two large monasteries, a huge stupa surrounded by numerous votive and commemorative stupas and a large number of sculptures such as Buddha figures – some colossal ones, Bodhisattva images, Tara, Heruka, Jambhala, Kurukulla and Hariti.

The great monastery at this place is a marvel of Buddhist architecture found in brick masonry with an impressive and decorated gate at the entrance opening into a spacious courtyard surrounded on two sides by closed cells and a chamber housing a colossal Buddha figure at the back. The monastery was in two storeys as appears from the ruins. Celebrated in epigraphic records as Ratnagiri Mahavihar, this place was a centre of learning, particularly Yoga philosophy, during hey days between 6th to 12th century A.D. Udayagiri, located five kilometers away is also an imposing Buddhist site with a huge monastery complex. A brick stupa along with a number of votive stone stupas are also found nearby. Close by we find a stepped well and another monastery. Lalitagiri, the third point of the triangle, is also full of Buddhist antiquities. At the apex of the site, a stone--------- sairika stupa during its exposure had revealed the sacred remains, probably of the Enlightened one, preserved carefully in a series of caskets of stone, silver and gold. This makes Lalitagiri foremost amongst Buddhist sites of Orissa. Excavation at the place by A.S.I. has brought to light a 1st century A.D. chaitya structure, a large monastery and large number of Buddhist sculptures. The Sculpture Shed nearby preserves a large number of colossal Buddha and Bodhisattva figures such as Vajrapani, Padmapani, Vajrasattva, Manjusri, etc.

Kuruma near Konark in Puri district has a smaller brick monastery and Buddhist sculptures like Yamantaka, Avalokitesvara, Padmapani and crowned Buddha. Banpur near Balugaon on Chilika lake has the distinction of yielding a large number of Buddhist bronzes, now preserved in the Orissa State Museum at Bhubaneswar. Buddhist stupas are found at Aragada atop a hill of the same name and at Paragalpur and Syamasundarpur. Remains of monasteries are seen at Solamnpur, Ganiapalli, Khadipada and opposite Jajpur across Vaitarani river. Buddhist sculptures are found at Ayodha, Bhubaneswar, Baneswaranasi, Brahmabana and Boud. The most ancient Buddhist centre is Dhauli where we find the major rock edict of Asoka, one of the two places in Orissa to have Asokan edicts, the other being at Jaugada in Ganjam district.The recently built Santistupa (in early 1970s) on the western apex of the Dhauli hill has enhanced its importance as a Buddhist centre. For the history of Buddhism this place holds special significance as the place of the Kalinga war in 261 B.C. after which Asoka embraced the path of spiritual conquest and foreshook the path of military conquests.

Architecturally the Buddhist viharas in Orissa were conceived as places of residences for Buddhist monks as well as their prayer hall at the centre with a sanctum at the back centre and cells surrounding the hall and an entrance gate at the front. Both bricks and stones were used as building materials. The stupas in Orissa are mainly commemorative and votive types, with the largest stupa having usual features found at Ratnagiri

In conformity with the origin and growth of post Gupta temple architecture in India, we have in Orissa early temples at Mahendragiri, Jajpur, Bhubaneswar and Bankada near Banpur of Khurda district. Besides a number of sculptural and architectural specimens are found in the above places which were evidently from early temples which could not survive. These along with the surviving earlier temples in Orissa clearly indicate the origin and growth of a separate regional style in ancient Orissa like that of the early Pallava architecture at Mahabalipuram or early Chalukyan architecture at Aihole and early temples in parts of north and central India.

In the evolution of temple architecture, the sikhara or curvilinear spire type ultimately became the dominant form in Orissa. Some of the earlier temples, now existing at Bhubaneswar and other places, represent the mature products of the sikhara type. The Orissan temple architecture by reason of its own distinct individuality and long history of evolution soon came to acquire for itself a nomenclature – the Kalinga.

The temple building activities in Orissa started with the advent of Sailodbhava kings (circa AD.575 to 736). After the Sailodbhavas, the Bhauma – Karas (AD 736 to 940), the Somavamsis (circa A.D. 885 to 1110) and the Imperial Gangas (A.D. 1110 to 1435) ruled successively as masters of the area. Amongst the above four dynasties, the Somavamsis and the Gangs were prolific builders and have left to us a large number of temples. Though temples belonging to different periods dot each nook and corner of Orissa, we find concentration of temples in known religious centers and important places like Jajpur in Jajpur district, Chaudwar in Cuttack district. Bhubaneswar in Khurda district, Konark and Puri in Puri district and Ranipur-Jharial in Balangir district. But Bhubaneswar takes the pride of place in having a large number of extant temples built during all the above dynastic periods and it becomes a unique place for the study of the development of Orissan architecture and sculpture.

In the beginning, an Orissan temple, in the manner of Gupta temples, consisted of a square sanctum with a sikhara and a rectangular mukhamandapa (porch). The mukhamandapa, known in Orissan temple terminology as jagamohana, had pillars inside it to support the flat roof. We find jagamohana of this type at Niladriprasad, near Banpur and Parasurameswara temple at Bhubaneswar dated to seventh century A.D.

The pillars inside the jagamohana disappeared gradually in the Bhauma-kara period and with the use of the cantilever principle the load of the ceiling was taken by pilasters provided on the inner walls of the jagamohana. In plan it retained the rectangular form but became more restricted lengthwise. The jagamohana of the Vaital, Sisireswar, Mohini and Markandeswara temple at Bhubaneswar bear evidence to this.

During the period from A.D. 600 to 950 we also find a gradual transformation in the sanctum proper or the rekha deula. Its exterior plan underwent changes. The earlier temple facades have three vertical sections known in temple terminology as raha paga or the central vertical section and konika paga or corner vertical section as low projections. This resulted in a squarish appearance of the exterior plan of the temple known then as a triratha temple. But with the change in the subsequent periods, the triratha form of the temple plan transformed into the pancharatha temples. The change was due to the increase in the number of vertical sections on the facades by addition of subsidiary vertical sections called anuraha paga and their bold projection. This resulted in a round like shape of the exterior plan of the sanctum. In the Ganga period the number of pagas increased and we find saptaratha and even a navaratha plan in the temple at Bhaskareswara at Bhubaneswar.

Side by side, there was noticeable transformation on the elevation profile of the rekha deula. In the earlier stage the sanctum rises from the ground level abruptly and the sikhara gradually tapers inside as it rose in height. By the time of the Somavamsis, the tapering is only from the top portion of the sikhara or gandi, and it takes a sudden inward curve to the base of the beki or the neck, below the amalaka.

The Somavamsi period witnessed a formative phase in the temple architecture of Orissa with the introduction of the pancharatha plan, the square jagamohana and the division of the vertical sections of the cube of the jagamohana in the manner of the rekha deula. The height of the jagamohana increased with the introduction of stepped pyramidal roof or pidha deula. Towards the middle of the eleventh century A.D. both the rekha and pidha deulas are fully developed as evident in the Brahmeswar and the Lingaraja temple at Bhubaneswar. There was also experimentation to go in for higher structures and large temple complexes.

During the rule of Imperial Gangas, who succeeded the Somavamasis, we find two important developments in Orissan architecture. The first is the introduction of the plinth. All the temples built during this period have a raised platform making the temples further high.

The second important feature introduced in this period is the addition of two more chambers, natamandira or the dancing hall and bhogamandapa or the offering hall, along the axial plan of the rekha and pidha structures. We find the raised plinth as well as the natamandira and bhogamandap in the Lingaraja temple, the Parvati temple inside the Lingaraj temple complex, the Ananta Vasudeva temple at Bhubaneswar and the Jagannath temple at Puri,. But the famous temple of Sun God at Konark has only the natamandir and that too detached from the general plan of the main temple. Generally the natamandira has a flat roof and the bhogamandap is a pidha structure. The four chambered plan of a temple complex continued and there was no further elaboration on the plan of a temple either horizontally or vertically during the subsequent periods.

Apart from Hindu temples, we find at least two examples where the temple has been used as a place of worship by the Jains as well as the Buddhist. At Ratnagiri in Jajpur district we have a temple (circa 11th century A.D.) housing a Mahakala image. The temple is located close to the monasteries and stupas at the place. Similarly, a group of temples house Jaina Trithankara and Sasana Devi figures at Subei in the district of Koraput. These can be dated to the 10th – 11th century A.D.