Apart from these divisions, all Jain communities are differentiated into laymen and members of the order or Yatis, literally strivers. It is recognized that laymen cannot observe the five vows. Killing, lying, and stealing are forbidden to them only in their obvious and gross forms: chastity is replaced by conjugal fidelity and self-denial by the prohibition of covetousness. They can also acquire merit by observing seven other miscellaneous vows (whence we hear of the twelvefold law) comprising rules as to residence, trade, etc. Agriculture is forbidden since it involves tearing up the ground and the death of insects. Mahâvîra was succeeded by a long line of teachers sometimes called Patriarchs and it would seem that their names have been correctly preserved though the accounts of their doings are meagre. Various notices in Buddhist literature confirm the idea that the Jains were active in the districts corresponding to Oudh, Tirhut and Bihar in the period following Mahâvîra's death, and we hear of them in Ceylon before our era. Further historical evidence is afforded by inscriptions[270]. The earliest in which the Jains are mentioned are the edicts of Asoka. He directed the officials called "superintendents of religion" to concern themselves with the Niganṭḥas[271]: and when [272] he describes how he has provided medicine, useful plants and wells for both men and animals, we are reminded of the hospitals for animals which are still maintained by the Jains. According to Jain tradition (which however has not yet been verified by other evidence) Samprati, the grandson of Asoka, was a devout patron of the faith. More certain is the patronage accorded to it by King Khâravela of Orissa about 157 B.C. which is attested by inscriptions. Many dedicatory inscriptions prove that the Jains were a flourishing community at Muttra in the reigns of Kanishka, Huvishka and Vasudeva and one inscription from the same locality seems as old as 150 B.C. We learn from these records that the sect comprised a great number of schools and subdivisions. We need not suppose that the different teachers were necessarily hostile to one another but their existence testifies to an activity and freedom of interpretation which have left traces in the multitude of modern subsects.