Which religion or how many of them were there in this land, before the advent of AchAryAl? It becomes known from the 'Shankara Vijaya' texts that there was the vEdic religion of
sanAdhana dharmA and there were other seventy-two heterodox sects. But, among the non-vEdic faiths, the predominant one was only Bhudhism. The majority of the general public and of
the intellectual class, which carried out the philosophical research, have been either with the sanAdhana vaidhIka dharma or with Bhudhism. Other faiths had only a small group of
following here and there. Though the small groups of followers of these splinter faiths had very vigorously embraced and followed their respective paths - Even now, are we not
witnessing the adherents of various 'isms' and 'schools' following their ideologies rather vigorously though the size of following in terms of numbers could rather
be meager - in general the religious scene then was such that it could be divided into two big groups such as vaidhIka matham and Boudham.
Those who followed this sanAthana-dharma-vaidhIka-matham are known by the name - 'SmArthAs'. [*The word*] SmArthAs means those who follow smrithis. Smrithi means dharma shAsthrAs. The work that properly collects, collates, classifies the dharmAs enunciated at various places in vEdAs and cogently presents them as a single source of information so as to guide different sections of the society, regarding their code of conduct - prescribing the dos and don'ts for a jIvan right from its conception in the mother's womb to its birth, growth, learning phase, marriage, procreation and finally till its cremation after the death - through a set of rules is dharma shAstra. They are also known as smrithis. Those who follow them are SmArthAs. The followers of vEdic religion, addressed today as 'Hindus', were originally known only by this name [*SmArthAs*].
Neither the 'exclusive' upAsanA of Vishnu nor the 'exclusive' upAsanA of Shiva had been advocated by dharma shAstras. All the 'vEda pradhipAdhya' deities (those mentioned in the vEdAs) are considered to be equal here. There is nothing wrong in choosing any one of them for upAsanA. It would be creditable, if the upAsanA is carried out with the basic understanding that all the deities are essentially one in nature. SmArthAs do pUjA for five deities such as sUryan, ambAl, mahA Vishnu, PillayAr and paramEswaran as indicated by the verse, 'Adhithyam-ambikAm- vishnum-gananAtham- mahEshwaram'. As five deities are worshipped, this is known as 'PanchAyathana pUjA'. One can have additional devotion (prIthi) towards one's favorite (ishta) deity. In the same family, Parama Sivan could be the ishta dEvathA for the elder brother while mahA Vishnu could be for the younger one. They wouldn't get separated into two different faiths such as Saiva - Vaishnava, because of this [*difference*]. Without getting split into two distinct sub sects, both Shiva and Vishnu upAsakAs had even matrimonial alliances between them. The common ground for all of them was - vEdAs. The 'karmAnushtAnAs', advocated therein were also the common basis for them.