The saiva Nayanar saints and vaishnava Alvar saints of South India spread the concept of bhakti among different sections of the society irrespective of caste and sex during the period between the 7th and the 10th century. Some of these saints hailed from the lower castes and some were women. The saint poets preached bhakti in an intense emotional manner and tried to promote religious egalitarianism. They ignored rituals and traversed the region several times singing, dancing and advocating bhakti. The Alvar and Nayanar saints used the Tamil language and not Sanskrit for preaching and composing devotional songs. Thus the movement could acquire a popular base. The South Indian bhakti saints used to criticize the Jains and Buddhists who enjoyed a privileged status at the courts of South Indian monarchs during that period. They won over many adherents of Buddhism and Jainism both of which by then became rigid and formal religions. These saint-poets simultaneously resisted the domination of the orthodox Brahmins by making bhakti accessible to all without any caste and sex discrimination. But the South Indian bhakti movement also had drawbacks. It never consciously proposed Brahmanism or the varna and caste systems at the social level. It was integrated with the caste system and the lower castes continued to suffer from myriad social disabilities. There was no elimination of Brahmanical rituals such as worship of idols, recitation of the Vedic mantras and pilgrimages to sacred places in spite of the overriding stress on bhakti as the superior mode of worship. The Jains and Buddhists were its principal targets not the Brahmins. This perhaps was also the reason why the Brahman dominated temples played an important role in the growth of South Indian bhakti movement. The ideological and social foundations of caste system were not challenged by the South Indian saint poets. As a result, the bhakti movement of the south in the long run strengthened that hierarchical system rather than weakening it. Ultimately after the movement reached its zenith in the 10th century, it was gradually incorporated by the traditional Brahmanical religion. Despite these constraints, the South Indian bhakti movement in its heyday succeeded in championing the cause of religious equality and consequently, the Brahmins had to accept the right of the low caste to preach, to have access to bhakti as a mode of worship and to have access even to the Vedas. When the popularity of the bhakti movement in South India was on the wane,the concept of bhakti was defended at the philosophical level by some gifted vaishnava Brahmin scholars (acharyas). Ramanuja (11th century) was the first among them. He gave philosophical justification for bhakti. He tried to establish a careful balance between orthodox Brahmanism and popular bhakti which was open to all.Though he did not support the idea of the lower castes having access to the Vedas, he advocated bhakti as a mode of worship accessible to all including the Sudra and even the outcastes. While propagating bhakti, he did not observe caste distinctions and even tried to eradicate untouchability. Nimbarka, a Telegu Brahman, is believed to have been a younger contemporary of Ramanuja. He spent most of his time in Vrindavan near Mathura in North India. He believed in total devotion to Krishna and Radha. Another South Indian vaishnavite bhakti philosopher was Madhava who belonged to the 13th century. Like Ramanuja he did not dispute orthodox Brahmanical restriction of the Vedic study by the Sudra. He believed that bhakti provided alternate avenue of worship to the Sudra. His philosophical system was based on the Bhagvat Purana. He is also believed to have toured North India. The last two prominent vaishnava acharyas were Ramananda (late 14th and early 15th century) and Vallabha (late 15th and early 16th century).