It would appear that the Hindu religious leaders were apprehensive of the growing popularity of the Jains and the Buddhists. This led to the intemperate language and the determined propagandist methods adopted by the leaders of the Bhakti movements. Though the early Alvars of the 6th century, as the Vaishnavite men of the religion were called, were more tolerant, from the 7th century onwards both the Saiva Nayanmars and the Vaishnava alvars adopted an attitude of stern hostility towards Jainism and Buddhism.

The Bhakti Movement was essentially founded in South India and later spread to the North during the late medieval period. This Movement itself is a historical-spiritual phenomenon that crystallized in South India during Late Antiquity. It was spearheaded by devotional mystics (later revered as Hindu saints) who extolled devotion and love to God as the chief means of spiritual perfection. The Bhakti movement in South India was spearheaded by the sixty-three Nayanars (Shaivite devotees) and the twelve Alvars (Vaishnavaite devotees), who disregarded the austerities preached by Jainism and Buddhism but instead preached personal devotion to God as a means of salvation. These saints, some of whom were also women, spoke and wrote in local languages like Tamil and Telugu and travelled widely to spread their message of love and devotion to everyone, irrespective of caste, colour and creed.

South India`s 75 Apostles of Bhakti is the twelve Alvars (also, Aazhvaars, Aazhwaars) and sixty-three Nayanmars (also Nayanars, Naayanars, Naayanmaars). They were all great devotees of the Lord most of whom came from the Tamil region. Of these Appar, Sambandar and Sundarar were authors of the Tevaram, a collection of standard Saivite canonical literature. Manikkavachakar of the 9th and perhaps early 10th century was the fourth of this illustratious group of Saiva bhakti-ites. Kannappa nayanar karaikkal ammai, kochchenger cholan and few others listed among the saiva saints belonged to pre 6th century while the rest lived between then and the late 8th century.

Among the Vaishnavites there were twelve Alvars of whom Pey, Bhudam and Poygai called Mudal Alvars lived in the 6th century and are supposed to have been contemporaries. Nammalvar considered by Vaishnavas, as the greatest among the Alvars was a great and true mystic and the author of a thousand verses collectively called Tirywaymozhi; he was Velala saint. His hymns are treated as equal in spiritual merit to the Vedic hymns. Of the alvars perialvar andak and kulasekhara of kerala were among the latest chronologically. Tirumangai mannan, a robber chief turned devotee, composed the largest number of verses in the Nalayariram i.e, the collection of 4000 devotional hymns sung by the twelve Alvars.

The Bhakti movement especially its Saivite wing set out to achieve two purposes and they were equally onerous. The first was to stem a heretical tide of the mass popularity of Jainism and Buddhism and to reclaim the people to sort of Hindu orthodoxy. The second was to convert the kalamukhas kapalikas pasupatas and a variety of other primitive sects, which exulted in violent orgies and indulged in barbarous superstition, which did not exclude a belief in and practice of human sacrifice and dealing in crematorial relics. The Mattavilasa Prahansana of Mahendravaramna I and some allusions in the periyapurnama of Sekkilar point to this situation. So the twin concerns of the Bhakti-ites were to prevent external heresy and internal religious disorders so that a reformation and Counter Reformation were simultaneously undertaken. By the end of the 9th century at least by the time of andal of srivilliputtur and Manikavachakar the famous author of the reputed tiruvachakam , the situation has been completely redeemed i.e. from the point of view of Bhakti leaders; this qualification is needed because we know that primitive Saivism though deprived of its more objectionable features was still popular in some quarters, and this is shown by its prevalence as late as the reign of Rajendra I (Chola) in Tiruvorriyur and other religious centres. The followers of the Saktha religion (worship of Shakti female of generative energy) at time degenerated. But Shaktism of a sort has persisted even in high quaters like a Adi Sankara himself.

In the development of religion in the Tamil country in particular the following tendency is noticeable and is to be remembered. A considerable segment of this development may be described as an attempt on the part of continuously reforming Hinduism to adjust itself to the changing situation created by the Jainas and Buddhist- popularity that waxed and waned by turns.

The Hindu bhakti movement reached its culmination with the collection and editus of the Vaishnava and Saiva hymns by Nathamuni and Nambiander Nambi respectively in the late 10th and 11th centuries. The standardization of the canonical texts was followed by other texts being added to the corpus as part of the total. But the Bhakti movement, which obviously was a departure from the sacrificial Vedic religion, or the intellectual Upanishadic pursuits, embarrassed the Hindu revivalists and so it became incumbent on their part to link the devotional hymns to the Vedic tradition. Hence Ramanuja in his Sri Bhasya and Madhva in his commentary on the Brahmasutras compromised Bhakti with Vedas and created Vaishnavite theism. Sankara of kaladi in Kerala, who lived earlier in the 8th century (788 to be precise) along with Kumarila Bhatta recreated the ancient Vedic brahmanical thought and established Smartaism to which all the non Vaishnava Brahmins are now affiliated. He preached a philosophical monism. He promotes the great doctrine of maya or illusion which to the Hindu mind was so alluring.

A number of commentaries on the 4000 Vaishnava hymns by erudite scholars have comedown to us. Among these commentarors Periavachan pillai is considered to be the greatest. The writings of these scholars spread Sr Vaishnava religio-philosophical ideas far and wide. A number of esoteric texts called Rahasyas were also written and among these Sri Vachna Bhushanam ranks very high.