The most renowned as well as the wisest and most powerful king of this dynasty was Gagik I. (990–1020), under whom the country enjoyed its period of greatest prosperity. The danger of the Arabs was past, but now a new peril threatened the East, that of the Seljukian Turks, who came from Central Asia in search of a new country. Persia and Mesopotamia fell before them and they entered Armenia. Several of the Armenian princes offered them stout resistance with some success, but, fearing that this success was only temporary, others transferred themselves and their subjects to more secure parts of the country. The Seljuks conquered Persia and established a Persian kingdom of their own, but the new Persia was no longer Zoroastrian, but Mohammedan. Armenia again became a battlefield. The Greeks also claimed the city of Ani, and this led to many conflicts in which the Armenians made a brave defence. The town, however, fell through treachery and the Greeks devastated some parts of the country, treating the inhabitants no better than the Arabs and the Seljuks had done. In order to weaken the power of Armenia, they also made attempts to exterminate the native princes and nobles. About the same time, the Seljuks again invaded Armenia and completed the desolation which the Greeks had begun. They wrought great destruction in Ani. The last king of the Bagratuni dynasty was unable to re-establish his kingdom and was killed by the Greeks. His two sons and his grandson were poisoned. So ended the race of the Bagratuni whose dynasty had lasted 160 years. During the rule of this house, the country had a period of rest and the energies of the people were directed to the restoration and development of the country. The ruined monasteries and churches were rebuilt, schools were again established; commerce, arts, and handicrafts throve. This was a particularly flourishing time for the national architecture, which now assumed a new character. Most of the Armenian abbeys and churches were built during this time, and as these places had always been seats of learning, alternative erudition revived, original writing and the transcription of manuscripts going on briskly within the convent walls. The literature of this period is chiefly of a religious character. In it we see traces of Arabic influence—the influence of the eighth century, when Arabic literature was at its zenith. The chief debt of Armenian literature to the Arabs is the introduction of rhyme, which is first found in Armenian verse in the eleventh century. In dealing with this period, as we are only concerned with Armenian poetry, we must leave unmentioned the historians and other famous prose writers.