Beneath a temple thought to mark the location of the Buddha's birth, archaeologists may have discovered the physical roots of the religion: an ancient tree shrine that predates all known Buddhist sites. The archaeological record of Buddhism stretches back to the time of Ashoka, an Indian emperor who enthusiastically embraced the religion in the 3rd century BC and built many temples. The sage known as the Buddha though, probably lived about three centuries earlier. The remains of one of Ashoka's temples lie at Lumbinini in Nepal, which many recognise as the Buddha's birthplace. As part of his conservation work, Robert Coningham at Durham University, excavated below the temple foundations. He found evidence of pre-Ashokan stonework and, below that, signs of a timber structure that was radiocarbon dated to between 800 and 550 BC. When the surrounding soil was examined it was found to contain the remains of ancient tree roots, but was strangely free of the debris usually left by human occupation. This suggests that a tree grew at the centre of the wooden structure, and that the area around it was regularly cleaned, just as Buddhist tree shrines are cleaned today.