Tamil emerges as a distinct clade within the Dravidian languages long after Vedic Sanskrit distinguishes itself within Indo-Aryan. The latter is the older literary tradition likewise (and indeed, among the oldest of the Indo-European literary traditions, up there with the Anatolian languages and Mycenaean Greek in its antiquity). To take another step back, we might ask whether Indo-Aryan or Proto-Dravidian establishes itself on the Indian subcontinent first. But this is rather foggy prehistory, and there are no answers which can be given with the confidence which would be lent by contemporaneous texts. Nonetheless, the tendency is to assume that Proto-Dravidian-speaking peoples preceded Indo-European migrations.