As Renfrew put it in his archly-titled review of Mallory’s book – ‘They ride horses, don’t they?’ – the horse has assumed “an almost mythical signifi… - Colin Renfrew

[This] episode of elite dominance which brought the indo-Aryan branch of the Indo-European family to India (…) may have been as early as the floruit of the Indus civilization (…)

[Supporters of Renfrew’s theory] “have tried to render the Indo-Iranian problem moot. They argue that the Indo-Iranian branch was somehow divided from the main body of Proto-Indo-European before the colonists brought agriculture to the Balkans. Greek and Indic are thus separated by millenniums of linguistic change - despite the close grammatical correspondences between them (... these correspondences probably represent shared innovations from the last stage of PIE).”

The balance of the evidence, as recently usefully reviewed by Shaffer, is in favour of the presence of an Indo-European speaking population during the Harappan civilization, and not exclusively later. At the same time, the strong continuities between that Harappan civilization and its antecedents, right back to the earlier Neolithic, are becoming more and more evident.