This section is from the book "Some Contributions Of South India To Indian Culture", by S. Krishnaswami Aiyangar. Also available from Amazon: Some Contributions of South India to Indian Culture.
This special development in the south of the orthodox systems of Brahmanism of the north apparently took form with the rise of the Sungas to power in northern India. Pushya-mitra's was perhaps the first organised effort for the revivification of Brahmanism in the face of a foreign enemy like the Greeks of Bactria thundering at the gates of orthodox India both in the political sense of a foreign enemy, and in the sacerdotal conception of heretics in religion. This opposition, although comparatively short-lived in the case of Pushya-mitra and his successors, seems to have put a new heart into the southerners of the orthodox creed, and given them the occasion to organise themselves for any possible struggle against their rivals. Apart from the various references in Tamil literature to the north and of the claims put forward for conquest against the Aryans which ought to be referred to the period following - the period of Andhra dominance -the period of this religious ferment and activity seems referable to the period of revival under the Sungas and Kanvas. That such connection was maintained even politically is in evidence in the Kharavela inscription itself.