The sect[567] founded by Nimbârka or Nimbâditya has some connection with this poem. Its chief doctrine is known as dvaitâdvaitamata, or dualistic non-duality, which is explained as meaning that, though the soul and matter are distinct from God, they are yet as intimately connected with him as waves with water or the coils of a rope with the rope itself. This doctrine is referred to in the religious drama called Prabodhacandrodaya, probably composed at the end of the eleventh century. The Nimâvats, as the adherents of the sect are called, are found near Muttra and in Bengal. It is noticeable that this sect, which had its origin in northern India, is said to have been persecuted by the Jains[568] and to have been subsequently revived by a teacher called Nivâsa. This may explain why in the twelfth century Vishnuism flourished in the south rather than in the north.[569] Less is known of the Nimbârkas than of the other sects. They worship Kṛishṇa and Râdhâ and faith in Kṛishṇa is said to be the only way to salvation. Kṛishṇa was the deity of the earliest bhakti-sects. Then in the fourteenth and fifteenth centuries there was a reaction in favour of Râma as a more spiritual deity, but subsequently Vallabha and Caitanya again made the worship of Kṛishṇa popular. Nimbârka expressed his views in a short commentary on the Vedânta Sûtras and also in ten verses containing a compendium of doctrine.[570] 3 As among the Śivaites, so among the Vishnuites of the south, history begins with poet-saints. They are called the twelve Âr̤vârs.[571] For the three earliest no historical basis has been found, but the later ones seem to be real personalities. The most revered of them is Namm'âr̤vâr also called Sathagopa, whose images and pictures may be seen everywhere in south India and receive the same reverence as figures of the gods.[572] He may have lived in the seventh or eighth century A.D.[573] The chronology of the Âr̤vârs is exceedingly vague but if the praises of Śiva were sung by poet-saints in the seventh century, it is probable that the Vishṇu worshippers were not behindhand. Two circumstances argue a fairly early date. First Nâthamuni is said to have arranged the hymns of the Âr̤vârs and he probably lived about 1000 A.D. Therefore the Âr̤vârs must have become classics by this date. Secondly the Bhâgavata Purâṇa[574] says that in the Kali age the worshippers of Nârâyaṇa will be numerous in the Dravidian country, though in other parts found only here and there, and that those who drink the water of the Kaveri and other southern rivers will mostly be devotees of Vâsudeva. This passage must have been written after a Vishnuite movement had begun in the Dravidian country.[575]