Early in the seventh century after Christ, the religion of Islam was established in Arabia. By the commandments of this new religion the use of alcohol was absolutely forbidden, and it is supposed that those who had been used to alcohol began to use opium and hemp drugs as substitutes, the fact that these two drugs were not explicitly mentioned being sufficient sanction, apparently, for their use. It seems certain that with the spread of Islamism, the use of opium as a stimulant became more widely diffused. The Arabs were at that time, to all intents and purposes, masters of the eastern seas. They made long voyages, and carried on a trade with India and China, and from contemporary literature it has been definitely established that it was the Arabs that introduced the poppy, and a knowledge of its properties, into China. It is probable that opium was used as a stimulant in India also, at this time, but nothing is definitely known about this, and the history of the production and use of the drug before the sixteenth century is obscure. There are many indications, however, that the opium habit came into India in the eighth century, when the Arabs invaded and conquered Sind; and as the habit spread with the wanderings of the Arabs, there is much in the surmise. From this time, up to the end of the eleventh century, the Mahomedan invaders brought the greater part of India under their rule or influence, and in Portuguese Chronicles, written in the sixteenth century, the cultivation of the poppy, the opium habit, the production of opium, and its export are talked of as established things. Authorities on India conclude, from the inherent reluctance of the Indian to rapidly adopt new habits or crops, that the opium habit, and the cultivation of the poppy for opium, must have taken at least three hundred years or so to develop over such large areas.