The Buddha, who lived in India in the 6th century bc, challenged the religious teachings of the Brahmans, who dominated Indian civilization at the time. An early convert to Buddhism was Bimbisara, king of Magadha, but its most extensive development was under the Mauryan empire of Asoka in the 3rd century bc, when there existed what has reasonably been described as a Buddhist civilization. By the end of the Mauryan empire in the early 2nd century bc, Buddhism had already developed internal divisions in its beliefs and practices and, although in the subsequent centuries it both spread to other areas and continued to contribute to Indian civilization, it lost its dominant role in that development. Early in the present era a new form of Buddhism appeared, known as the Mahayana or ‘Great Vehicle’, which had a more flexible doctrine. It was this form of Buddhism that found its way from India through Central Asia to China in the 1 st or 2nd century ad. Very large numbers of Buddhist monuments survive in India itself, including stupas and rock-cut cave temples. Tibet also has large numbers of Buddhist monuments. Buddhism was first introduced to Tibet from India during the reign of king Sron-brtsan-sgam-po (c620-649) and revived in the late 10th century by Rin-c’en-bzan-po (958-1055) and the Indian teacher Atisa. Its archaeological manifestations are the numerous temples, monasteries and shrines found throughout the Tibetan cultural area. The earliest temples (Jha-k’an) are small, rectangular in plan and have massive inward sloping walls and flat roofs. The original foundations of the Royal Dynastic period (c620-842) are usually distinguished by tall dressed stone pillars topped by a roof-like canopy and sometimes bearing a dedicatory incription. The first true monastery in Tibet was that of bSam-yas, built by K’ri-sron-Ide-brtsan (755-7797). In its original form it had a large seven-storey temple surrounded by eight ancillary buildings to house the monks. mC’od-rten, a type of shrine very common in Tibet, are symbolic buildings modelled on the Indian stupa. They are psycho-cosmograms, representing the Buddhas and their teachings, and are made of dressed stone or sun-dried brick with a plaster facing. They normally contain a cavity for religious relics and the largest examples contain actual rooms. Buddhism reached Southeast Asia in the early centuries of the Christian era as part of the process of Indianization. It reached Japan rather later: the Mahayana Buddhism was officially introduced to the Japanese court in 538, but it had probably been known in the country for some time before that. After an internal struggle over its acceptance, Buddhism became part of the adminstrative measures which the emerging central government adopted to tighten its control over the provinces. Syncretism with the indigenous nature worship began by the 8th century, but Buddhism remained the religion of the elite until the 13 th century, when Pure Land Buddhism met an enthusiastic reception from the masses.