Architecturally, their history begins with the gateways of the Tope at Sanchi; the southern or oldest of these was almost certainly erected during the reign of the first Satakarni in the first quarter of the 1st century--while Christ was teaching at Jerusalem--and the other three in the course of that century. It ends with the completion of the rail at Amravati, which with almost equal certainty was commenced in the first quarter of the 4th century, and completed about A.D. 450.[20] Between these two monuments there is no great difficulty in filling up the architectural picture from the caves, at Nassick and Ajunta, and other places in western India, and more materials will no doubt eventually be discovered. The history of this dynasty is more than usually interesting for our purposes, as it embraces nearly the whole period during which Buddhism reigned almost supreme in India. It became the state religion, it is true, two centuries earlier under Asoka, but there is no reason for believing that the Vedic religion or Brahmanism vanished immediately. During the first four centuries, however, of the Christian Era we have not a trace of a Hindu building or cave, and, so far as any material evidence goes, it seems that Buddhism at the time was the religion of the land. It cannot, of course, be supposed that the Hindu faith was wholly obliterated, but it certainly was dormant, and in abeyance, and, to use a Buddhist expression, the yellow robes shone over the length and breadth of the land. It was during the reign of these Andras, though not by them, that the fourth convocation was held by Kanishka, in the north of India, and the new doctrine, the Mahayana, introduced by Nagárjuna--a change similar to that made by Gregory the Great when he established the Church, as opposed to the primitive forms of Christianity, at about the same distance of time from the death of the founder of the religion. My impression is, that this convocation was held in the last quarter of the first century of our era, probably 79. Certain at least it is, that it was about that time that Buddhism was first practically introduced into China, Thibet, and Burmah, and apparently by missionaries sent out from this as they were from the third convocation. It was towards the end of the reign of the Andras that Fa Hian visited India (A.D. 400). As his objects in doing so were entirely of a religious nature, he does not allude to worldly politics, nor give us a king’s name we can identify; but the picture we gather from his narrative is one of peace and prosperity in so far as the country is concerned, and of supremacy for his religion. Heretics are, it is true, mentioned occasionally, but they are few and far between. Buddhism was then certainly the religion of the north, especially in the north-west of India; but even then there were symptoms of a change, in the central provinces and outlying parts of the country.