One of the early movements that was important to the development ofVaishnavism was the ancient Pancharatra movement, whose sacred texts or Agamasconsisted of detailed procedures to worship the sage Narayana, an ancientincarnation of Vishnu. Since the Pancharatra Agamas originated from Narayanahimself, they're followed by pretty much all mainstream Vaishnavas today.
But there was a time when some people, particularly the Purva Mimamsaschool of Hindu philosophy, rejected the Pancharatra Agamas because theybelieved that the Vedas were the only legitimate Hindu scriptures.The early Sri Vaishnava Acharya Yamunacharyacomposed a work called the Agama Pramanya to defend the scriptural authority ofthe Pancharatra Agamas.
That isn't the only work that Yamunacharya composed, however. He alsocomposed a work called the Kashmir Agama Pramanya, which is now lost. ButYamunacharya alludes to it in this excerptfrom his (regular) Agama Pramanya, in the course of refuting the argument thatthe customs of Pancharatra-following Brahmins are contrary to Vedic practices:
Those who perform the forty sacraments which areenjoined by the Ekayana scripture ... properly follow the rules laid down bythe grihyasutras of their own shakha and do not abdicate their brahminhoodbecause they fail to follow the rites of a different shakha[.]... It followsthat the non-observance of certain rites enjoined by different shakhas does notmean that either one forfeits his brahminhood - that the Ekayana shakha ispreterpersonal scripture has been enlarged upon in the Treatise on theValidity of Kashmira Agama..
But there was a time when some people, particularly the Purva Mimamsaschool of Hindu philosophy, rejected the Pancharatra Agamas because theybelieved that the Vedas were the only legitimate Hindu scriptures.The early Sri Vaishnava Acharya Yamunacharyacomposed a work called the Agama Pramanya to defend the scriptural authority ofthe Pancharatra Agamas.
That isn't the only work that Yamunacharya composed, however. He alsocomposed a work called the Kashmir Agama Pramanya, which is now lost. ButYamunacharya alludes to it in this excerptfrom his (regular) Agama Pramanya, in the course of refuting the argument thatthe customs of Pancharatra-following Brahmins are contrary to Vedic practices:
Those who perform the forty sacraments which areenjoined by the Ekayana scripture ... properly follow the rules laid down bythe grihyasutras of their own shakha and do not abdicate their brahminhoodbecause they fail to follow the rites of a different shakha[.]... It followsthat the non-observance of certain rites enjoined by different shakhas does notmean that either one forfeits his brahminhood - that the Ekayana shakha ispreterpersonal scripture has been enlarged upon in the Treatise on theValidity of Kashmira Agama..