After the fall of Pagan, Upper Burma, of which we must now speak, passed through troubled times and we hear little of religion or literature. Though Ava was founded in 1364 it did not become an intellectual centre for another century. But the reign of Narapati (1442-1468) was ornamented by several writers of eminence among whom may be mentioned the monk poet Sîlavaṃsa and Ariyavaṃsa, an exponent of the Abhidhamma. They are noticeable as being the first writers to publish religious works, either original or translated, in the vernacular and this practice steadily increased. In the early part of the sixteenth century[161] occurred the only persecution of Buddhism known in Burma. Thohanbwâ, a Shan who had become king of Ava, endeavoured to exterminate the order by deliberate massacre and delivered temples, monasteries and libraries to the flames. The persecution did not last long nor extend to other districts but it created great indignation among the Burmese and was perhaps one of the reasons why the Shan dynasty of Ava was overthrown in 1555. Bayin (or Bureng) Naung stands out as one of the greatest personalities in Burmese history. As a Buddhist he was zealous even to intolerance, since he forced the Shans and Moslims of the northern districts, and indeed all his subjects, to make a formal profession of Buddhism. He also, as related elsewhere, made not very successful attempts to obtain the tooth relic from Ceylon. But it is probable that his active patronage of the faith, as shown in the construction and endowment of religious buildings, was exercised chiefly in Pegu and this must be the reason why the Sâsanavaṃsa (which is interested chiefly in Upper Burma) says little about him. His successors showed little political capacity but encouraged religion and literature. The study of the Abhidhamma was specially flourishing in the districts of Ava and Sagaing from about 1600 to 1650 and found many illustrious exponents. Besides works in Pali, the writers of this time produced numerous Burmese translations and paraphrases of Abhidhamma works, as well as edifying stories.